This is mandated by the C99 standard, and clang 15 produces zillions of
warnings otherwise.
* devel/ftoption.h, include/freetype/config/ftoption.h,
include/freetype/internal/ftmemory.h, src/autofit/afhints.h,
src/autofit/afmodule.c, src/autofit/aftypes.h, src/base/ftadvanc.c,
src/base/ftdbgmem.c, src/base/ftstream.c, src/bdf/bdflib.c,
src/truetype/ttinterp.c: Replace identifiers of the form `_foo` with `foo_`.
This ancient option stayed completely undocumented. Given that the 'cff'
driver requires the 'psnames' module, it makes no sense today to have this
macro.
* src/cff/cffdrivr.c (cff_services), src/cff/cffobjs.c (cff_face_init):
Remove corresponding conditional code.
* src/sfnt/ttcolr.c (FT_PaintFormat_Internal): New enumeration values
`FT_COLR_PAINTFORMAT_INTERNAL_VAR_SKEW`,
`FT_COLR_PAINTFORMAT_INTERNAL_SKEW_CENTER`, and
`FT_COLR_PAINTFORMAT_INTERNAL_VAR_SKEW_CENTER`.
(read_paint): Handle new enumeration values.