Give CC to gir-scanner

From:
https://github.com/Alexpux/MINGW-packages/blob/master/mingw-w64-harfbuzz/0001-give-cc-to-gir-scanner.all.patch
diff --git a/src/Makefile.am b/src/Makefile.am
index 5832f75..acedaa0 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -361,6 +361,7 @@
 INTROSPECTION_GIRS = HarfBuzz-$(HB_VERSION_MAJOR).0.gir # What does the 0 mean anyway?!
 INTROSPECTION_SCANNER_ARGS = -I$(srcdir) -n hb --identifier-prefix=hb_ --warn-all
 INTROSPECTION_COMPILER_ARGS = --includedir=$(srcdir)
+INTROSPECTION_SCANNER_ENV = CC="$(CC)"
 
 HarfBuzz-0.0.gir: libharfbuzz.la libharfbuzz-gobject.la
 HarfBuzz_0_0_gir_INCLUDES = GObject-2.0