No effect yet; service functions will be implemented later on.
Everything is guarded with TT_CONFIG_OPTION_GX_VAR_SUPPORT.
* include/freetype/internal/services/svmetric.h: New file.
* include/freetype/internal/ftserv.h
(FT_SERVICE_METRICS_VARIATIONS_H): New macro.
* include/freetype/internal/tttypes.h (TT_Face): New field `var'.
* src/sfnt/sfobjs.c: Include FT_SERVICE_METRICS_VARIATIONS_H.
(sfnt_init_face): Initialize `face->var'.
* src/truetype/ttdriver.c: Include FT_SERVICE_METRICS_VARIATIONS_H.
(tt_service_metrics_variations): New service.
(tt_services): Updated.
* src/truetype/ttpic.h: Updated.