Improve the NMake Makefiles that is used to re-generate demos.h(.win32)
by re-generating the gtk3-demo Visual Studio projects, so that one would
no longer need to do that manually.
Update the build instructions accordingly.
This improves the source generating process by:
* Generating the sources in the libgtk build directory, so that we do not
pollute the source tree.
* Support generating gtk[private]typebuiltins.[c|h] in the Visual Studio
projects by using NMake internally.
* Update the projects and the introspection build files so that the generated
sources and headers can be found.
This makes the rest of the sources that are generated being put in GDK's build
directory for the Visual Studio projects, instead of being placed in GDK's
source subdir, so that:
* We can avoid polluting GDK's source tree.
* The Visual Studio builds won't interfere with the Meson builds.
Update the project files to look for the generated sources and headers in the
right places, as well as making the introspection builds look for the generated
sources as well.
Also remove the gtk3-gen-srcs property sheets and put the relevant parts in the
corresponding gtk3-build-defines property sheets, to clean things up a bit.
We can regenerate demos.h.win32 with or without the font features demo
by using the regenerate-demos-h-win32 target with or without secifying
the FONT_FEATURES_DEMO=1 flag on the NMake command line.
Instead, rely on the mechanism that we already have to set the platform string
appropriately, eg:
i686-pc-vsXX for 32-bit x86 builds
x86_64-pc-vsXX for x64 builds
aarch64-pc-vsXX for arm64 builds
Look in the include/harfbuzz directory that is under the pre-defined prefix
directory, as Pango 1.44.x and later pulled in HarfBuzz headers for all builds
