meson: gdk: win32: add skeleton bits for win32 backend

Won't even build, configure bits still missing.

gdk/meson.build

@@ -180,7 +180,7 @@ endif
 
 gdk_backends = []
 gdk_backends_gen_headers = []  # non-public generated headers
-foreach backend : ['broadway', 'wayland', 'x11', 'mir']
+foreach backend : ['broadway', 'wayland', 'x11', 'mir', 'win32']
   if get_variable('@0@_enabled'.format(backend))
     subdir(backend)
     gdk_deps += get_variable('gdk_@0@_deps'.format(backend))

gdk/win32/meson.build

@@ -0,0 +1,50 @@
+gdk_win32_sources = files([
+  'gdkcursor-win32.c',
+  'gdkdevicemanager-win32.c',
+  'gdkdevice-virtual.c',
+  'gdkdevice-win32.c',
+  'gdkdevice-wintab.c',
+  'gdkdisplay-win32.c',
+  'gdkdisplaymanager-win32.c',
+  'gdkdnd-win32.c',
+  'gdkevents-win32.c',
+  'gdkgeometry-win32.c',
+  'gdkglcontext-win32.c',
+  'gdkglobals-win32.c',
+  'gdkkeys-win32.c',
+  'gdkmain-win32.c',
+  'gdkmonitor-win32.c',
+  'gdkproperty-win32.c',
+  'gdkscreen-win32.c',
+  'gdkselection-win32.c',
+  'gdkvulkancontext-win32.c',
+  'gdkwin32cursor.h',
+  'gdkwin32display.h',
+  'gdkwin32id.c',
+  'gdkwindow-win32.c',
+])
+
+gdk_win32_public_headers = files([
+  'gdkwin32cursor.h',
+  'gdkwin32display.h',
+  'gdkwin32displaymanager.h',
+  'gdkwin32dnd.h',
+  'gdkwin32glcontext.h',
+  'gdkwin32keys.h',
+  'gdkwin32misc.h',
+  'gdkwin32monitor.h',
+  'gdkwin32screen.h',
+  'gdkwin32window.h',
+])
+
+install_headers(gdk_win32_public_headers, subdir: 'gtk-4.0/gdk/win32/')
+install_headers('gdkwin32.h', subdir: 'gtk-4.0/gdk/')
+
+gdk_win32_deps = [ # FIXME
+]
+
+libgdk_win32 = static_library('libgdk-win32',
+  gdk_win32_sources, gdkconfig, gdkenum_h,
+  include_directories: [confinc, gdkinc],
+  c_args: ['-DGDK_COMPILATION', '-DG_LOG_DOMAIN="Gdk"', '-DINSIDE_GDK_WIN32'],
+  dependencies: [gdk_deps, gdk_win32_deps])

meson.build

@@ -37,6 +37,7 @@ x11_enabled      = get_option('enable-x11-backend')
 wayland_enabled  = get_option('enable-wayland-backend')
 broadway_enabled = get_option('enable-broadway-backend')
 mir_enabled      = get_option('enable-mir-backend')
+win32_enabled    = false # FIXME
 
 mkmarshal    = find_program('build_marshal.py')
 glib_marshal = find_program('glib-genmarshal')