* include/freetype/ftbitmap.h (FT_Bitmap_Embolden): New declaration.
* include/freetype/ftoutln.h (FT_Outline_Embolden): New declaration.
* src/base/ftbitmap.c (ft_bitmap_assure_buffer): New auxiliary
function.
(FT_Bitmap_Embolden): New function.
* src/base/ftoutln.c (FT_Outline_Embolden): New function.
* src/base/ftsynth.c: Don't include FT_INTERNAL_CALC_H and
FT_TRIGONOMETRY_H but FT_BITMAP_H.
(FT_GlyphSlot_Embolden): Use FT_Outline_Embolden or
FT_Bitmap_Embolden.