build: add a gdi check for windows

Incidentally this seems wrong in the configure as well because only gl-win32
depends on it instead of also making direct3d depend on this (as I did here).

wscript

@@ -447,6 +447,10 @@ video_output_features = [
             fragment=load_fragment('cocoa.m'),
             compile_filename='test.m',
             framework_name=['Cocoa', 'IOKit', 'OpenGL'])
+    } , {
+        'name': 'gdi',
+        'desc': 'GDI',
+        'func': check_cc(lib='gdi32')
     } , {
         'name': '--wayland',
         'desc': 'Wayland',
@@ -510,6 +514,7 @@ video_output_features = [
     } , {
         'name': '--gl-win32',
         'desc': 'OpenGL Win32 Backend',
+        'deps': [ 'gdi' ],
         'func': check_statement('windows.h', 'wglCreateContext(0)',
                                 lib='opengl32')
     } , {
@@ -571,6 +576,7 @@ video_output_features = [
     }, {
         'name': '--direct3d',
         'desc': 'Direct3D support',
+        'deps': [ 'gdi' ],
         'func': check_cc(header_name='d3d9.h'),
     }
 ]

wscript_build.py

@@ -359,8 +359,7 @@ def build(ctx):
         ( "video/out/vo_wayland.c",              "wayland" ),
         ( "video/out/vo_x11.c" ,                 "x11" ),
         ( "video/out/vo_xv.c",                   "xv" ),
-        ( "video/out/w32_common.c",              "os-win32" ),
-        ( "video/out/w32_common.c",              "os-cygwin" ),
+        ( "video/out/w32_common.c",              "gdi" ),
         ( "video/out/wayland_common.c",          "wayland" ),
         ( "video/out/x11_common.c",              "x11" ),