mutex and memory allocation subsystems. This is an incremental check-in. (CVS 5218) FossilOrigin-Name: a03c5af115889f477e17187a198a7d2d40bc76bf
FossilOrigin-Name: 4bdfe1419c536fec5b3c0a7fbe3d0ff52f183f43
each for unix, w32, and os2. (CVS 4312) FossilOrigin-Name: fc5cd71aef5ac194f51d73350d773d532020967e