Split OPT make variable into OPT and BASECFLAGS. The latter contains those

compiler flags which are necessary to get a clean compile.  The former is
for user-specified optimizer, debug, trace fiddling.  See patch 640843.

Add /sw/lib and /sw/include to setup.py search paths on Darwin to take
advantage of fink goodies.

Add scriptsinstall target to Makefile to install certain scripts from
Tools/scripts directory.