Our build files were relying 'sysroot' to find gexiv2.h but this is
not possible with Apple Clang om which sysroot points to macOS SDK.
So, exotic environments like Homebrew were failing. Let's fix this.
This is a followup of previous commit. We must set the win_subsystem
option on executable() so that the result binary is compiled as a GUI
application (and doesn't output a console every time).
The previous commit is still needed and is what allows us to control
when to actually display a console.
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
This gives a big cleanup in the meson.build files of the plug-ins.
It's also quite a bit more maintainable, since anything that changes in
libgimp's dependencies, linkage, ... doesn't have to be copy-pasted into
each plug-in.
