[Pixman] [BUG REPORT] pixman_glyph_cache_create leaks memory that it allocates

[Yuri]

google-perftools memory profile on a gtkmm-based app shows that there is 
0.3MB of memory left by pixman_glyph_cache_create.


pixman should free all memory that it allocates. For example, if the app 
will load the gtkmm UI dynamically, this memory will be permanently lost 
every time, resulting in the memory leak.


pixman-0.34.0


Yuri