Although this question has been answered and it helped the original questioner, I also had a problem compiling GIT which aborted building Sage. After searching and finding only pieces of Git and Mac compilation problems I was able to get the build to work by exporting NO_APPLE_COMMON_CRYPTO=1 in the command shell and by issuing make NO_CURL=1 instead of just make. Note that exporting NO_CURL=1 didn't work. My machine is an early 2008 Macbook Pro running OSX 7.5. Hopefully this will save someone else a few hours of frustration.