Apple made a number of changes to Xcode 4. The SDKs were moved, the entire
Developer folder was moved, and PowerPC support was removed. The script
will now adapt to those changes and should be future-proofed against
additional changes in case Apple moves the Developer folder ever again.
Also, the minimum OS X version compiler option was removed, so that the
framework can be built against the latest SDK but still run in older cats.
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
