[mutter/cogl-pango-fix] Add fallback for semi-private symbols in Pango

[Emmanuele Bassi <ebassi src gnome org>]

commit 7d2f9fdfdc862a760d3ef38d6e5ed67c059b9cc0
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Sun Jul 7 10:30:47 2019 +0100

    Add fallback for semi-private symbols in Pango
    
    Pango dropped the PANGO_ENABLE_BACKEND and PANGO_ENABLE_ENGINE symbols,
    so we need to add our own defines to avoid breaking the build.

 cogl/cogl-pango/cogl-pango-render.c | 7 +++++++
 1 file changed, 7 insertions(+)
---
diff --git a/cogl/cogl-pango/cogl-pango-render.c b/cogl/cogl-pango/cogl-pango-render.c
index d005e9412..3edf97483 100644
--- a/cogl/cogl-pango/cogl-pango-render.c
+++ b/cogl/cogl-pango/cogl-pango-render.c
@@ -39,6 +39,13 @@
 #define PANGO_ENABLE_BACKEND 1
 #endif
 
+#ifndef PANGO_UNKNOWN_GLYPH_WIDTH
+#define PANGO_UNKNOWN_GLYPH_WIDTH 10
+#endif
+#define PANGO_UNKNOWN_GLYPH_HEIGHT
+#define PANGO_UNKNOWN_GLYPH_HEIGHT 14
+#endif
+
 #include <pango/pango-fontmap.h>
 #include <pango/pangocairo.h>
 #include <pango/pango-renderer.h>