Fix linking problem when built with -no-opengl

When -no-opengl was used then it was not automatically pulling in the
needed Windows libraries as it was not loading opengl.prf to get them
from.

Change-Id: Ic00717b2327a1f7cf05f55bcde7a7308e36c19e9
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>

src/winextras/winextras.pro

@@ -43,6 +43,7 @@ QMAKE_DOCS = $$PWD/doc/qtwinextras.qdocconf
 
 DEFINES += NTDDI_VERSION=0x06010000 _WIN32_WINNT=0x0601
 LIBS_PRIVATE += -lole32 -lshlwapi -lshell32
+win32:!qtHaveModule(opengl):LIBS_PRIVATE += -lgdi32
 
 OTHER_FILES += \
     doc/qtwinextras.qdocconf \