We're mixing a lot of styles in the Meson build files. This is an
attempt at making everything slightly more consistent in terms of
whitespace and indentation.
If glslc is found, rebuild the shaders from GLSL to SPIR-V; otherwise,
we're just going to use the built files we have committed in the source
repository.
When building GTK+ straight from the repository without any assistance
from packaging tools, we need to trigger system-wide updates, like the
icon theme cache update, or the schema compilation.
We can build the name of the input and output files for the Wayland
protocols we use from the protocol name, stability, and version. This is
similar to how the autotools build does it, except much more clear and
without shelling out twice to sed just to resolve the Makefile rule.
We need to check if the linker flags we use are available, depending on
the platform, and we need to ensure that the shared library is
versioned appropriately.
GTK symbols are not visible by default, and only the ones annotated with
_GDK_EXTERN (and wrapper macros) are exported. We need to define
_GDK_EXTERN during the configuration, depending on the platform and
compiler we use.
The autotools build checks the version of GLib we are depending on in
order to generate the appropriate GLIB_VERSION values for the
min-required/max-allowed defines.
We have to work around some ordering problems here. We still
manage to keep most of the guts in modules/input/meson.build,
so it's not too ugly overall.
(The autotools build solves this with a 'make -C ../../input/modules'
inside gtk/Makefile, but that's not something we can or want to do.)
Remove workaround for gcc bug (Meson does that now), and
construct the right config.h defines for the headers on
the fly instead of listing them in the build file, which
is more error prone.
Add back dependencies on libgdk_dep and libsk_dep which are declared
dependencies. We removed this before because these declarations had
link_with: lines that dragged in the static libgdk.a and libgsk.a libs
which are linked into libgtk-4.so anyway and thus shouldn't be used
when linking internal exes/tools against libgtk-4. Remove the static
libs from the declared dependencies and have libgtk link those in
explicitly, so that the declared deps now just provide all the built
dependencies and include dirs and such for declared libgtk_dep users
such as the internal exes/tools, which want all the generated gsk/gdk/gtk
headers to exist before attempting to compile anything against the
gtk+ headers.
