gl: Decouple win32 window and wgl context

With ANGLE, win32 window can be used with gles and egl

gst-libs/gst/gl/gstglcontext.c

@@ -66,7 +66,7 @@
 #include "cocoa/gstglcontext_cocoa.h"
 #endif
 #if GST_GL_HAVE_PLATFORM_WGL
-#include "win32/gstglcontext_wgl.h"
+#include "wgl/gstglcontext_wgl.h"
 #endif
 #if GST_GL_HAVE_PLATFORM_EAGL
 #include "eagl/gstglcontext_eagl.h"

gst-libs/gst/gl/meson.build

@@ -671,7 +671,7 @@ if need_platform_wgl != 'no' and need_win_win32 != 'no'
     gl_sources += [
       'win32/gstglwindow_win32.c',
       'win32/gstglwindow_win32.c',
-      'win32/gstglcontext_wgl.c',
+      'wgl/gstglcontext_wgl.c',
     ]
     enabled_gl_winsys += 'win32'
     gl_winsys_deps += gdi_dep

gst-libs/gst/gl/wgl/gstglcontext_wgl.h

@@ -21,7 +21,7 @@
 #ifndef __GST_GL_CONTEXT_WGL_H__
 #define __GST_GL_CONTEXT_WGL_H__
 
-#include "gstglwindow_win32.h"
+#include "../win32/gstglwindow_win32.h"
 
 G_BEGIN_DECLS