multimedia/vlc: Added optional Wayland support

Signed-off-by: Christoph Willing <chris.willing@iinet.net.au>

multimedia/vlc/README

@@ -12,6 +12,15 @@ are detected at build time, they will be included. Conversely if
 optional packages are not available at build time, vlc will continue
 to build with a reduced feature set.
 
+Support for Wayland is a special case. It is not supported by default
+but can be enabled setting the WAYLAND environment variable to "yes"
+when running the SlackBuild e.g.
+  WAYLAND=yes sh vlc.SlackBuild
+This support also requires additional SBo packages wayland-egl and
+wayland-protocols. It also depends on the qt5 package having been
+built with wayland support i.e. wayland package was installed when the
+qt5 package was built.
+ 
 The vsxu SlackBuild is now optional for x86 machines; removed from
 REQUIRES since it does not compile on arm machines at the moment.
 

multimedia/vlc/vlc.SlackBuild

@@ -29,7 +29,7 @@
 
 PRGNAM=vlc
 VERSION=${VERSION:-20170406_8268fe0}
-BUILD=${BUILD:-1}
+BUILD=${BUILD:-2}
 TAG=${TAG:-_SBo}
 
 if [ -z "$ARCH" ]; then
@@ -58,6 +58,7 @@ fi
 
 DOCS="ABOUT-NLS AUTHORS COPYING INSTALL NEWS README THANKS"
 qtversion="--enable-qt=4" ; [ "${QTVERSION:-5}" != "4" ] && qtversion="--enable-qt=5"
+wayland="--disable-wayland" ; [ "${WAYLAND:-no}" != "no" ] && wayland="--enable-wayland"
 
 # In an ordinary virtual machine, since a different kernal is running,
 # a unique dbus id is needed.
@@ -103,6 +104,7 @@ LDFLAGS="$SLKLDFLAGS" \
   --localstatedir=/var \
   --build=$ARCH-slackware-linux \
   $qtversion \
+  $wayland \
   --enable-merge-ffmpeg \
   --enable-libva=no \
   --with-kde-solid=no \