Looks like ender's name can't be used verbatim in the encoding used
for the Polish translation. Use his name as previously appeared in
the Polish translation.
Replace diacritical marks, which aren't supported in the target
encoding, with equivalent precomposed characters.
Replace underscore with ampersand in mnemonics.
In configure.ac, add --enable-windows-installer option (off by
default), which should be set to generate the necessary files for
the installer translations during the build. Using this option is
only supported when building from git, since the installer files
are not included in source tarballs.
Rename setup.isl.desktop.in to setup.isl.in, and instruct intltool
to treat it as an .ini file explicitly.
Delete generated message files during make clean.
Use intltool for managing the translations for the Windows
installer, instead of manually maintaining the translated message
files.
The message files are generated in the source directory, under
build/windows/installer/lang, as part of the build, and can be
subsequently used to build the installer, as before.