meson: add initial winstore support

This patch tries to replicate configure.ac (at the time of writing)
from line 407 - 438, except the strict aliasing check. Libraries such as
ole32 are linked by default by meson, so those have been omitted.
Another difference: the check has been moved out of the mingw check.

This is not meant to be functional just yet, but having the winstore
option gives a starting point for further support.

config.h.meson

@@ -604,8 +604,8 @@
 /* host which ran configure */
 #mesondefine VLC_COMPILE_HOST
 
-/* TODO: Define to 1 if you want to build for Windows Store apps */
-#undef VLC_WINSTORE_APP
+/* Define to 1 if building for Windows Store. */
+#mesondefine VLC_WINSTORE_APP
 
 /* Define to 1 if build machine is big endian */
 #mesondefine WORDS_BIGENDIAN

meson.build

@@ -277,6 +277,8 @@ endif
 #
 
 have_mingw = false
+have_win_desktop = false
+have_win_store = false
 mingw_libs = []
 
 if host_system == 'windows'
@@ -363,6 +365,9 @@ windows_version_test = '''
             mingw_libs += mingwex_lib
         endif
 
+        # TODO: enable when meson 0.63 is required
+        # add_project_dependencies(mingw_libs, language: ['c', 'cpp'])
+
         # Check for fnative-struct or mms-bitfields support for MinGW
         if cc.has_argument('-mms-bitfields')
             add_project_arguments('-mms-bitfields',
@@ -384,6 +389,18 @@ windows_version_test = '''
             language: ['c', 'cpp'])
     endif
 
+    # Check if we are building for Windows Store
+    if get_option('winstore_app')
+        have_win_store = true
+        cdata.set('VLC_WINSTORE_APP', 1)
+        add_project_arguments('-DWINSTORECOMPAT', language: ['c', 'cpp'])
+        windowsappcompat_lib = cc.find_library('windowsappcompat')
+        # TODO: enable when meson 0.63 is required
+        # add_project_dependencies(windowsappcompat_lib, language: ['c', 'cpp'])
+    else
+        have_win_desktop = true
+    endif
+
 endif
 
 if cc.has_argument('-Werror-implicit-function-declaration')
@@ -573,6 +590,10 @@ endif
 
 libcompat_sources = []
 
+if have_win_store
+    libcompat_sources += 'gai_strerror.c'
+endif
+
 # Check all functions in libcompat_functions array
 foreach f : libcompat_functions
     if cc.has_function(f[0], prefix : vlc_conf_prefix + f[1], dependencies: [rt_lib, socket_libs])

src/meson.build

@@ -54,6 +54,9 @@ min_windows_version_test = '''
     libvlccore_deps += cc.find_library('bcrypt')
     libvlccore_deps += cc.find_library('winmm')
     libvlccore_deps += cc.find_library('normaliz')
+    if have_win_store
+        libvlccore_deps += cc.find_library('runtimeobject')
+    endif
     if cc.compiles(min_windows_version_test.format('_WIN32_WINNT_WIN8'), name: 'Compiling for Win8+')
         libvlccore_deps += cc.find_library('synchronization')
     endif