Build LLVMgold.so on FreeBSD using cmake.
Patch by Stephen Checkoway.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177233 91177308-0d34-0410-b5e6-96231b3b80d8
To avoid symbol clash, undefine PPC here. PPC may be predefined on some hosts.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177234 91177308-0d34-0410-b5e6-96231b3b80d8