Merge from vendor branch BMAKE:

Merge from vendor branch BMAKE:
Update to bmake 20081101 snapshot. The more important changes are:
- portability fixes for putenv
- man page updates
- fix processing of .END with -j
- fix some segmentation faults on parse errors
- debug output goes to stderr by default
- first round of fixes for A/UX
- fix crashes on long lines
- faster VarQuote
- fix use of ?= when the LHS contains variable references