the API is likely to change however.
* src/base/fttrigon.c (FT_Angle_Diff): fixing function, it returned
invalid values for large negative angle differences (resulting in
incorrect stroker computations, among other things)
* src/cache/ftccache.c (ftc_node_unlink): removing incorrect
assertion, and changing code to avoid hash table size contraction
* src/base/Jamfile, src/base/rules.mk, src/base/descrip.mms:
adding "ftstroker.obj" to default build, as optional component