Add g_Ctoc to list of acceptable g_* symbols in mono, for test-eglib-remap.

Add g_Ctoc to list of acceptable g_* symbols in mono, for test-eglib-remap.

In theory, this test is used to verify that no unknown glib symbols exist
in eglib. However, it's tripping on g_Ctoc which is not a glib (or eglib)
symbol, instead it comes from the IO layer - and glib symbols never use
uppercase characters anyway