- compile into linux64Gcc44, linuxGcc44 to avoid clashes during testing
- continue to use gmp-4.2.4 since gmp-4.3.x might be miscompiled with
  a system gcc-4.3.2

- added rules for gcc-4.3 in preparation for switching to gcc-4.4

- added 'clean' target for wmake/src/Makefile
  It is probably reasonable to separate the binaries from the rules (TODO)