* src/sdf/module.mk, src/sfd/rules.mk: New files.
* src/sdf/ftsdf.h (ft_sdf_raster): New forward declaration.
* include/freetype/ftmoderr.h (FT_MODERRDEF): Add error definition
for the 'sdf' module.
* include/freetype/internal/fttrace.h (FT_TRACE_DEF): Add trace
definition for the `sdf' module.
* modules.cfg (RASTER_MODULES): Add the `sdf' module to the list of
rasterizers.
Anuj Verma