Give CC to gir-scanner

From:
https://github.com/Alexpux/MINGW-packages/blob/master/mingw-w64-pango/0006-give-cc-to-gir-scanner.mingw.patch
[pangocairo] Allow backend selection

Based on:
https://github.com/Alexpux/MINGW-packages/blob/master/mingw-w64-pango/0008-allow-backend-selection.mingw.patch
Fix introspection includes

Inspired by:
https://github.com/Alexpux/MINGW-packages/tree/master/mingw-w64-pango