MacOSX-Framework: updates for Snowleopard

1) PPC64 appears to be an 10.5 only supported architecture, so I
forced 10.5 for 64bit if there is a need for PPC64, else 64bit only
does x86_64

2) proper "make clean" after every ./configure. fixes a bug where
subsequent runs the 32bit do not get compiled

3) Added a version numbering curl-$VERSION} rather than the "stock standard" A