Does not build on clang with GMP

[whiteknight]

Parrot was building with llvm/clang for a while, but recently it doesn't anymore. It fails when trying to link because it detects several of the GMP symbols are defined more then once. I do not know why it is having these problems, and I am not sure whether the issue is in GMP, Clang, or Parrot

I have been able to build with clang using this configuration command:

perl Configure.pl --cc=clang --ld=clang --link=clang --without-gmp