… function gimp_font_get_pango_font_description().
Also updating file-pdf-save which is the only plug-in using these right now.
Note that I am not fully happy with the new function
gimp_font_get_pango_font_description() because I experienced some weird behavior
in file-pdf-save which is that some fonts were wrong if this is called after
pango_cairo_font_map_set_resolution().
But let's say this is a first step looking for improvements.
New code uses pango_attribute_as_font_desc() which appeared with Pango 1.50.
Since it's currently present in Debian stable, I don't bother too much and bump
this dependency.
Also let's use the same version for pango, pangocairo and pangoft2. They all
come from the same project/repository, so we must likely expect them to be equal
(if they are not, there is likely a problem).
We already search for a compatible Python version in the root meson file, no
need to look up Python 3 again in the PATH, each time we run an external Python
script in the build.
This should hopefully fix#9687.
After discussion with Jernej, InnoSetup should now work better with rescaling
a big image properly to the window size, yet the ratio should still matter.
Apparently the welcome image is a hack and this is why it requires specific
ratio images. We don't use the big size yet, but since Jernej told me which
dimensions are expected, I already added the code for it to make it easier
later.
So anyway this code would allow us not to have to commit welcome images each
time, which are basically resized copy in BMP of the splash screen, slowly yet
surely filling up our repository with image duplicates.
After all, we develop a scriptable image editor! We should use it to edit images
and export in expected formats!
I only use this script for the devel installer for now, for testing and see how
it goes.
This allows our script-fu plugins to use the GIMP enum values, just like
all our other plug-ins know them.
In other words:
* Names are consistent with those of other plug-ins
* Introspectable enums are automatically added as they are added to the
introspection file, without even needing a recompile
* No need to keep track of our enum types anymore, as that is just a
redundant implementation of introspection in practice. This in turn
will let us simplify some of the pdb code
Let's make cfitsio an optional dependency, showing up in the final configure
output. The file-fits plug-in will just not be built when the dep is missing.
Switch to NASA-maintained cfitsio library for loading/exporting FITS images.
This allows us to import compressed FITS files (GZIP, HCOMP, PLIO, RICE) in
8/16/32 bit and float/double precision. It also simplifies export code using
the built-in cfitsio APIs.
- Lua, Javascript and Python were boolean defaulting to true, which was
installing them even when not available (and if not installed then, it
would show warnings at each run). Instead I make them features with
'auto' as default. In this default, we don't install when the
interpreters are absent.
- These 3 options can still be forced by setting them to 'enabled' (the
interpreters are not actually necessary during build).
- Vala behavior stay the same (and unlike other binding, you cannot
force it since it has a build step); it's only renamed to just "vala"
for consistency of option naming.
I noticed that in our CI meson job certain tests were skipped, which didn't
happen with autotools.
On examination I noticed these tests check for HAVE_XVFB_RUN. Even though
meson checks for xvfb-run etc, it doesn't set HAVE_XVFB_RUN.
Adding HAVE_XVFB_RUN allows the tests to run without skipping certain parts.
We don't want to fail the build configuration just because we can't test for
runtime dependencies. In such a case, just assume it's good as we at least have
libheif and we can compile.
Fixes:
> ../meson.build:756:2: ERROR: Can not run test applications in this cross environment.
Even though, some format support might be missing, since codecs can be added at
runtime, it can always change later without having to touch GIMP. Yet we won't
be able to edit the desktop file when this happens.
See new comments in #9080.
Without this change, meson outputs this warning:
> meson.build:868: WARNING: add_languages is missing native:, assuming languages are wanted for both host and build
From libheif >= 1.14.0, the pkg-config variable will become bogus and always
return 'yes' so we now need to check for codec avaibility at compile time the
same way we look for these at runtime.
It may seem irrelevant to do these checks since these codecs can be added
anytime later, but it's still very good information for packagers to immediately
see that we have runtime package missing.
The current code was wrong, hence was producing wrongly versioned shared
library files. This commit do it the same way as we do it on autotools build,
and additionally compute the library version (since "current:revision:age" gets
transformed into "(current - age).age.revision" by libtool, but meson doesn't
use libtool so we have to do this ourselves).
Now meson and autotools builds produce the same result at least. There are still
some points I'm wondering and which we should handle before GIMP 3.0 release:
* Since meson doesn't use libtool (and no .la files are created), should we
actually stick to libtool version scheme? It seems like some projects would
use semver instead. On the other hand libtool version gives a bit more info.
* Also it raises the question on whether we want the API version to be semver at
all or simply follow GIMP version? It used not to be much of a problem as we
wouldn't add features (hence new API) on micro version, yet now we can. So
GIMP program's version could not pass as semantic versioning. On the other
hand, having a diverging API version (whose minor version would increment
faster in particular, with regular micro version resets) would be confusing
too.
* If we keep libtool versioning, I'm thinking we should do it manually. It's
actually pretty easy with a good docs (or even just following GNU docs:
https://www.gnu.org/software/libtool/manual/html_node/Updating-version-info.html),
and simple to understand whereas the current code logic is very weird and we
end up with huge current and age values with complicated computation.
Note also that I raise the "Libtool versioning" section near meson.build top and
updated gimp_interface_age to be the same as on autotools currently.
The dl*() functions are in libc directly. This probably applies to all
*BSD too. And from what I read, it should even apply to macOS, even
though a libdl is present there (is it bogus?).
So let's make the libdl check proper by only make it mandatory on Linux
(on Windows it was already unchecked too).
Fix the Linux Input test to correctly only depend on whether or not the
header is present. Having X11 target is not enough (e.g. it breaks the
build for NetBSD and probably on all BSDs).
We were using GIMP_UNSTABLE extensively to differentiate development
from stable code. But there is actually another level of development
code. Basically GIMP_UNSTABLE tells you are on the development branch,
e.g. for current branches, that you are on 2.99.* versions (vs. 2.10).
This depends on the minor version oddness.
GIMP_RELEASE will tell you if it's a release or a in-between-releases
code. This works with the micro version which must be even on release.
Any odd number means you are basically using random git code.
There can be any combination of GIMP_RELEASE and GIMP_UNSTABLE. For
instance 2.99.12 is a release of the unstable branch, whereas 2.10.33 is
development code of the stable branch.
I use this first in the update code as we were using GIMP_UNSTABLE for
both concepts but it made it harder to test. Now:
* GIMP_DEV_VERSIONS_JSON environment variable is only available on
development code, not on release (whether stable or unstable).
* The weekly check limitation is also only for releases (dev code just
check at every startup to quickly detect issues and regressions).
* Whether to look on testing website or public website json file depends
on the code being a release or not.
* Finally only whether to check "DEVELOPMENT" or "STABLE" sections in
the json file depends on whether we are on stable or unstable
branches.
Fixes:
> gcc: error: unrecognized command-line options '-mmx'; did you mean '-mmmx'?
> gcc: error: unrecognized command-line options '-sse'; did you mean '-msse'?
This meson warning was only showing when configuring a cross-compilation
project.
Fixes:
> WARNING: Project targets '>=0.56.0' but uses feature deprecated since '0.55.0': meson.has_exe_wrapper. use meson.can_run_host_binaries instead.
Now that we bumped our meson requirement, meson is complaining about
several features now deprecated even in the minimum required meson
version:
s/meson.source_root/meson.project_source_root/ to fix:
> WARNING: Project targets '>=0.56.0' but uses feature deprecated since '0.56.0': meson.source_root. use meson.project_source_root() or meson.global_source_root() instead.
s/meson.build_root/meson.project_build_root/ to fix:
> WARNING: Project targets '>=0.56.0' but uses feature deprecated since '0.56.0': meson.build_root. use meson.project_build_root() or meson.global_build_root() instead.
Fixing using path() on xdg_email and python ExternalProgram variables:
> WARNING: Project targets '>=0.56.0' but uses feature deprecated since '0.55.0': ExternalProgram.path. use ExternalProgram.full_path() instead
s/get_pkgconfig_variable *(\([^)]*\))/get_variable(pkgconfig: \1)/ to
fix:
> WARNING: Project targets '>=0.56.0' but uses feature deprecated since '0.56.0': dependency.get_pkgconfig_variable. use dependency.get_variable(pkgconfig : ...) instead
For meson, I want to be particularly careful and not follow the "Debian
testing" rule as it bit us by the past for babl.
But this bump is probably OK:
* Debian stable has meson 0.56.2.
* meson 0.56.0 was released on 2020-10-30.
* GIMP 2.99 is a dev branch with no end release date yet.
This should also fix this warning at configuration time:
> WARNING: Project specifies a minimum meson_version '>=0.53.0' but uses features which were added in newer versions:
> * 0.55.0: {'Calling "add_dist_script" with File, CustomTarget, Index of CustomTarget, Executable, or ExternalProgram'}
We missed it until now because it was only happening with tarball builds
where gitversion_h could be a files() object, unlike in git builds.
- Setting an exec_dir variable is an error. As meson docs says, if
relative, it is installed relatively to prefix anyway: "If this is a
relative path, it is assumed to be relative to the prefix."
On the other hand, it would make problems if someone tried to set an
absolute bindir.
Moreover it is a lot clearer now. When we want to install in the
binary directory unconditionally, then get_option('bindir') is the
meson way, hence the way to go.
- On the other hand, the `gimp-debug-tool` is installed either in bindir
for Windows or macOS and libexecdir for all other platforms, at least
that's how it's set in the autotools build. So let's keep both builds
consistent.
- Make a hopefully clearer description for enable-default-bin option.
Let's clarify this is just about creating unversionning links pointing
to versionned files.
- Adding an item in the "Optional Features" part of the summary listing
during meson configure, for better discovery.
For the ".exe" extension on Windows, I wished we had an $(EXEEXT)
equivalent on meson rather than trying to set it ourselves (are there
other platforms where we must set a different extension?). But I could
not find any.
`meson dist` don't imply a reconfigure or a rebuild which is actually
not great as it means a wrong order of commands may create tarballs with
outdated data (typically: build, then pull new code, then dist).
Of course for our official tarballs, it should be fine as we don't
generate tarballs manually anymore, but through the CI. Yet, just to be
on the safe side, force-trigger a reconfigure then a build (which would
likely be very fast anyway in the common use case where we just did a
build right before).
Additionally the INSTALL.in file is not copied anymore in the tarball
and INSTALL will only be generated in git repositories.
Ironically, it is a test for the Windows platform but it cannot run on
Windows. First, because it expects a .so (which could be easily fixed),
but even more because from web search, it looks like the nm tool may not
exist on Windows (though I haven't checked).
Anyway we only ever ran it from Linux machines and up to now, it worked
just fine and was useful anyway. So let's go with it.
Also clean a bit remnants from older attempts to run this script.
Our meson build system was not properly building the enums.c file,
because they are versionned.
I did a similar trick as what I did for the pdbgen, which is that I used
a wrapper script around the existing perl script, which sets proper
options and generate a stamp file in the end (which is considered by
meson as the actual custom target, not the C file since it is generated
in the source dir).
The most important part is that the stamp file is a generated header
source (not just a random text file) which is **included** by the
generated C file. This is what will force meson to regenerate the C file
if the header is updated, **then** build using this new version, not use
an outdated versionned version (which would make for hard to diagnose
bugs), through the indirection of the intermediate stamp header.
See #4201.
See also: https://github.com/mesonbuild/meson/issues/10196#issuecomment-1080742592
Some of our calls to run_command() would have failed with future
versions of meson if we didn't set the "check" parameter. In particular,
in various calls, we don't want to fail the whole build configuration
when the command does (as it's an optional feature check). In such a
case, it is important to be explicit as future will default to fail
then.
Fixes:
> WARNING: You should add the boolean check kwarg to the run_command call.
> It currently defaults to false,
> but it will default to true in future releases of meson.
> See also: https://github.com/mesonbuild/meson/issues/9300
These changes make it possible to build against homebrew for mac
libraries. Homebrew stores it's libraries in seperate folders and so
blanket includes were not working.
PYTHONPATH is not needed and interferes with homebrew build.
langinfo.h is not on all systems apparently and/or the locale item we
test for may not be available everywhere. Actually even on Linux, after
testing more deeply, I could create cases where nl_langinfo() would not
return a result (if the locale is broken through environment variable
for instance). setlocale() seems to always return usable value so far,
so I fallback on it. As a last resort, I look at environment variables
(even though these may contain invalid contents.
As for Windows and macOS, I try to use more platform-specific methods.
In macOS in particular, as I understood from reports, GIMP follows
correctly the language preference order, which means we should not look
at a single (top) lang, but at the whole list of prefered languages as a
single settings to determine whether the language was changed or not.
Should fix on Windows:
> fatal error: langinfo.h: No such file or directory
and on macOS:
> error: use of undeclared identifier '_NL_IDENTIFICATION_LANGUAGE'
intltool has long been dead upstream. Let's not poke the dead corpse,
please.
This commit is quite large, but that's mostly since trying to support a
hybrid of both gettext and intltool with both Meson and Autotools was
really hard, so I stopped trying.
Due to gettext relying on quite some things being at the exactly right
place in the autotools build (like `ABOUT-NLS` and `config.rpath`) we
really needed to cleanup the `autogen.sh` to only call `aclocal` and
`autoreconf`. No more strange magic; I tried to do it without changing
too much in the file, and things just broke. If people want to do
something more custom, they can just change the script directly. This
change also uncovered some problems in our `configure.ac`, like using
deprecated macros.
The following major changes happened:
* meson: Changed `custom_target()` to `i18n.merge_file()` for all
supported file types
* Added `.its` and `.loc` files for the GIMP-specific XML formats, so
that gettext understands them
* For the `.isl` (Window installer stuff) file, there's no easy way to
do this in gettext, so instead we start from an XML file (again with
its own ITS rules etc), translate that with gettext, and then use
`xsltproc` with a bit of magic to output the .isl file for each
language
* the `po*/Makefile.in.in` files are migrated to `Makevars` files,
which gettext natively understands.
Fixes: https://gitlab.gnome.org/GNOME/gimp/-/issues/8028
Since the new AppStream URL types are only available since appstream
0.15.3.
Thanks to Eli Schwartz for notification of the availability of the
'version' option, even in find_program().
As told to us, this is the reference AppStream file testing tool, and it
understands more of the spec.
Also since commit 73e2e701da, appstream-util chokes on newer url types
from the spec. These tags are now supported both in appstream-util and
appstreamcli source code, except that appstreamcli had release 0.15.3,
available in Debian testing, whereas there were apparently no recent
appstream-glib/util release (and none since 2020). So for these various
reasons, let's go with the appstreamcli tool.
The only downside is that appstream package (where appstreamcli lives)
is not available on MSYS2, but since it's only an optional test tool for
XML files which should be common on all platforms, it's probably
acceptable.
For the build tool, we really don't need a recent GLib. Checking the few
function docs, GLib 2.2 is fine, which (looking at git logs) means any
version after 2002. At this point, it's nearly unneeded to add a minimum
required version, but let's be thorough.
Anyway really no need to block a build if we have an old build GLib,
which is completely enough, as long we have the recent host GLib.
As suggested by jeremyd2019 and Biswa96 of MSYS2 project, defining the
MNG_USE_DLL macro would trigger libmng header code to fix the calling
convention. This way, even the old detection code now works with Windows
32-bit.
The reason why we still stick to this old detection code is that the
pkg-config is likely not everywhere (e.g. in Debian package libmng-dev,
there is no `.pc` file). So the pkg-config test is good but we still
definitely need to keep our fallback more old-school test for this
dependency.
See this comment in particular:
https://github.com/msys2/MINGW-packages/issues/11136#issuecomment-1084627263
Note: I am unsure yet how to apply the same trick on the autotools test
because AC_CHECK_LIB() would allow us to tweak the cflags to define a
macro, but we also need to include libmng.h header, otherwise the
calling convention tweak is not run. It doesn't look to be feasible with
the autoconf macro, or at least I haven't found how yet.
The main problem was that file-mng would fail to build on Windows 32-bit
even though the lib was detected. Actually this is because there are
several possible calling conventions and this can be handled by defining
the proper macro. This macro is well defined in the pkg-config file, but
our build was not using it.
So let's change the test to use pkg-config first. If this fails, we
fallback to more basic method of finding the library. Additionally we
augment this fallback test with a function check (as we do already in
autotools) so that our configure test is reliable: we verify that the
lib is there **and** that symbols are visible. Otherwise we'd end up
with a successful configure test followed by a broken build (as until
now in meson).
See the nice explanation here and in next messages:
https://github.com/msys2/MINGW-packages/issues/11136#issuecomment-1083711452
The `link_with` arg only accept library targets which are the libraries
we build ourselves, whereas dependency objects (such as returned by
cc.find_library()) must be in the `dependencies` arg.
Yes me too, making a difference here kind of stun me a bit and I don't
get why it's needed, but so be it. Since this code dates back from the
original commit, I assume it means the directx option just never worked
with meson on Windows.
Fixes:
> ../meson.build:847:2: ERROR: Entries in "link_with" may only be self-built targets,
> external dependencies (including libraries) must go to "dependencies".
The build now successfully build the PDB files into the source folder
itself. Unfortunately it seems I can't get meson dependencies to work
properly, once more! I added a "sources" argument to the relevant
library() or static_library() but it still uses old versions to build
these. E.g. if I add an error on purpose to a pdb file, the next build
still passes, yet the second-next fails (as it should have before).
Note that I even tested a declare_dependency() with just the "sources"
arguments, because it says "sources to add to targets (or generated
header files that should be built before sources including them are
built)" (so I assume it means that it should be trigger a rebuild,
otherwise it's useless) but it's just not working. I'll investigate
more.
Still going with this for now, because at least generating the PDB
source was a big miss until now. But we should
GExiv2 0.14.0 was released last September. It has been on Debian Testing
since October. The MSYS2 repository for Windows also provides this
version now, and I have bumped the version used in gimp-macos-build. So
let's upgrade the requirement (for the dev branch only) so that we can
finally get rid of all the remaining annoying warnings relative to this
library.
Recent libtiff supports loading BigTiff automatically so we didn't have
anything to do there (as long as a recent libtiff was used). For
creating a BigTIFF though, we simply needed to add a "8" flag to
TIFFOpen/TIFFClientOpen when creating a new image (i.e. using "w8"
mode) as explained here in the "Implementation Strategy" section:
http://www.simplesystems.org/libtiff/BigTIFFProposal.html
What this commit does:
- Explicitly bump our libtiff requirement to version 4.0.0 or higher
(which is where BigTiff support appeared).
libtiff 4.0.0 was apparently released on 2011-12-22 and is available
on all current distributions, so it's probably not a problem.
- Switch to detect libtiff with a pkg-config test (added in libtiff
commit faf5f3eb before 4.0.0 release, so it's fine) instead of
function checks.
(Note: meson was already detecting for libtiff-4 with pkg-config,
which was obviously wrong since it should have mimicked autotools, but
well… then changes were minimal on meson)
- Add a new "bigtiff" boolean argument to the "file-tiff-save" PDB
procedure, FALSE by default. I set this as the first argument as I
figure that choosing the format you want is quite a major choice.
Unless I misunderstood something, since BigTIFF is really designed to
be an evolution of TIFF with a "minimum change strategy", i.e. mostly
using 64-bit instead of 32-bit offsets, everything which is possible
in TIFF will be in BigTIFF (and oppositely as well, except of course
having huge files) so there is no need to have 2 separate procedures.
- Adding this new argument to the GUI dialog as a checkbox.
- Tweak the load and export procedures' documentation strings to make
clear we support both TIFF and BigTIFF.
Note: interestingly there doesn't seem to be a separate mimetype for
BigTIFF so nothing to update on this side.
- Tweak the procedure labels too to mention BigTIFF. Since BigTIFF is
still a different format (though very closely resembling) from TIFF,
unlike some others which are just extensions embedded in a TIFF file
(like GeoTIFF we recently added), I figure it deserves to be
explicitly cited.
Though the Color and Symbolic icon themes will have a different build
process and naming scheme for their icons, the base list is meant to be
the same by maintenance principle. So I am moving out the lists to the
icons/ directory's meson file.
Bumping meson requirement to 0.53.0 because I need to ability to use a
variable as dictionary key (not only string literals), which appeared in
this version. Meson 0.53.0 was released 2020-01-07 and seem to be used
in any stable distribution released since 2020. In any case, it seems
widespread enough to bump it now for our dev branch.
Ok that was a bit of a mess with the 4 build cases (combinations of
meson, autotools, vector and raster icons). I *think* this is now OK.
Basically we still need to build the colorsvg2png tool even when
installing vector icons, just for the purpose of the 2 icons
dialog-question and gimp-wilber-eek which we compile into GLib resources
from PNG images.
Also it looks like I completely forgot to add the subdir meson.build in
icons/Color/.
Build-time tool, which basically just rasterize SVG images (it doesn't
do anything special like gtk-encode-symbolic-svg which creates special
PNG for GTK to recolor them).
It looks like I had this prepared since 2018 according to file header,
but I just never finished doing it! :P
Basically now PNG icons of the Color icon themes do not need anymore to
be committed in the repository. They will be generated from the SVG
icons.
Also adding a missing icon from the 16px list (the Playground icon for
Preferences dialog was needed in 16x16 as well, yet missing).
I realize that this module is available since meson 0.53.0 though our
current requirement is meson 0.50.0.
Note sure why meson was not popping any warning (normally it does when
we use a feature younger than the minimum requirement; but maybe this
doesn't work for modules).
Anyway this does the same thing without the 'fs' module, and maybe even
better (we know which icons should be converted or used from source, no
need to add any test logics here).
The whole logics of creating specially prepared PNG images for vector
icons (with gtk-encode-symbolic-svg) was absent. This option was
basically completely broken, yet we now know that we need the ability to
install PNG alternatives for the icons (see #6821).
This is a continuation of previous commit which is straightening a bit
our whole icon theme builds. Note though that more needs to be done
because I definitely still see room for more mess and far too much
duplication.
JPEG XL plug-in always imported all JXL images
in 32-bit float precision in the past.
Now it also supports direct import in 8-bit
and 16-bit integer precision too.
Also called "feature" option in meson, so that by default it depends on
auto-detection of the gi-docgen hence won't break the configuration when
the tool is missing (the feature is simply disabled).
Also move the program check into the root meson file, which is anyway
much better to have a better visibility of features, otherwise we'd end
up just having tests everywhere in any possible random directory of the
repo.
Finally add a line in the summary of the configuration step, displaying
the docs generation being enabled or disabled.
Part of the fix for #5863, which is to depend on newer version of GExiv2
where I contributed new APIs using GError-s instead of GLib warnings for
metadata tag issues.
Now Debian testing packages GExiv2 0.14.0 (and MSYS2 has 0.12.3) so
let's bump the dependency for our dev branch.
Not sure why this was set as optional in the meson build, as it was
already mandatory in the autotools build back then (and for as long as I
remember).
This is an official way to declare these plug-ins as now
unmaintained/deprecated.
Relevant plug-ins are:
1) help-browser (Displaying the docs): nowadays every desktop machine
has a browser. Let's just use whatever is the person's default
browser.
2) web-page (Web screenshot): it looks to me like every browser has this
feature by default now (I use it all the time in Firefox to get a
full-page screenshot, never in GIMP), even on mobile, I am told. It's
nice to have it in GIMP too, but not like absolutely necessary.
On the other hand:
1. It's a hell to build, with a lot of issues. We have regular issues on
our Flatpak-s. We don't manage to build it on our CI (only locally
apparently). Also it takes a crazy amount of time (like 90% of CI
build-time would be webkit).
2. From what I gather, new versions don't work on Windows anymore. Even
MSYS2 seems to have dropped the ball and don't try anymore.
Basically we would have a feature disparity from GIMP 3.0 (most
platform but Windows). We don't know when it will be resolved (if
ever) as it's been like this for years.
Now why we are keeping the code around instead of just removing
everything is that the topic tree in the help browser is useful and
comfortable to use. Ideally we should get some equivalent to help
browsing the help efficiently in the web docs as well (so basically
menus, web search and alike?). So I am told to keep the code around at
least for now to see if we can figure something out or improve the
situation.
Except for this point, we can consider the WebkitGTK plug-ins as
deprecated from GIMP 3.0 on.
This is untested on my side, because the bug only happens on native
builds with meson (our CI has cross-builds with meson and native builds
with autotools and I only do cross-builds locally) but I think/hope it
will work.
Basically we were using .full_path() because these rc files were also
used as input of some configure_file() calls which doesn't like custom
target objects as input (it wants strings or file objects). Yet a bug
in meson didn't like the colon used in native Windows full paths ('C:'
and such) when used in windows.compile_resources(). This has been fixed
by Luca Bacci in: https://github.com/mesonbuild/meson/pull/9368
Yet we just cannot depend on very early meson (or worse dev meson code).
On the other hand, if the input is a custom_tgt object, it uses the
object ID which we give as first parameter of custom_target() so we know
it's appropriately named without colons (such as 'gimp_plugins_rc').
Thus we should not bump into this issue again.
For the few usage in configure_file(), I just add a .full_path() only
when needed at call time.
Last but not least, I replace the bogus `meson --version` call by a
`python3 -c 'exit()'` as advised by Eli Schwartz:
2afa019c70 (note_1284951)
The reason is that it is apparently possible (or will be when some
reimplementation of meson will be done) that the `meson` executable
itself does not exist. On the other hand, `python3` should always be
there, as a mandatory dependency of the build tool.
In order to use an appropriate `python3`, I made the
pythonmod.find_installation() check required in our build (which should
not be a problem since it's a meson requirement as well), even when the
-Dpython option is false (this one depends on other requirements too
anyway, such as version and pygobject). This way I can call this meson
variable of discovered python in my bogus call, instead of calling a
(potentially different) python from PATH environment.
Jehan