Add workaround (CFLAGS+=-frerun-cse-after-loops) for breakage in GCC 2.95.3.
It's backwards compatible, so no need for OSVERSION or other checks like that.
Also add new var - MAKE_JOBS, which allows you to adjust the -jN argument (I
wanted this 'cause with more CPUs I can compile with MAKE_JOBS=4 or greater).
Methinks this kind of thing belongs in bsd.port.mk, but anyway. I can now
compile (with MAKE_JOBS=4) qt 1.45 in less than 4 minutes on my dual