Make `FT_FACE_FLAG_VARIATION' work.

* include/freetype/internal/tttypes.h (TT_Face): Remove
`is_default_instance'; this can be replaced with a combination of
`FT_IS_VARIATION' and `FT_IS_INSTANCE'.

* src/cff/cffdrivr.c (cff_get_advances): Updated.

* src/sfnt/sfdriver.c (sfnt_get_ps_name), src/sfnt/sfobjs.c
(sfnt_init_face): Updated.

* src/truetype/ttdriver.c (tt_get_advances), src/truetype/ttgload.c
(TT_Process_Simple_Glyph, load_truetype_glyph, IS_DEFAULT_INSTANCE),
src/truetype/ttgxvar.c (tt_set_mm_blend): Updated.
* src/truetype/ttgxvar.c (TT_Set_MM_Blend, TT_Set_Var_Design):
Handle `FT_FACE_FLAG_VARIATION'.

* src/type1/t1load.c (T1_Set_MM_Blend, T1_Set_MM_Design): Handle
`FT_FACE_FLAG_VARIATION'.
9 files changed