Don't build compiler-rt arm code on darwin. Fixes PR12918.
Don't build compiler-rt arm code on darwin. Fixes PR12918.

I'm not sure if this is the right fix, but this has been broken
for two weeks and pleas for review were ignored. It seems to do
the right thing.



git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@158466 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt