unsupported -ggdb flag is used with clang 3.1
I upgraded to Xcode 4.3 which has clang 3.1:
Apple clang version 3.1 (tags/Apple/clang-318.0.45) (based on LLVM 3.1svn)
Thread model: posix
After running ((%autoconf; CC=clang ./configure; make%)) clang complains about -ggdb:
clang: warning: argument unused during compilation: '-ggdb'
Also, the clang manual page notes for -g -O0 will generate the best information:
-g Generate debug information. Note that Clang debug information works best at -O0. At higher optimization levels, only line number information is currently available.