Distinguish between build command and traditional build command (used
exclusively for the traditional build system (Makefile + pkg-config))
where for Windows the only build command that works is the MSYS-based
make, (e.g., not the MinGW-based mingw32-make).
Adjust default number of parallel builds from 8 to 4.
svn path=/trunk/; revision=13121
Alan W. Irwin