[PATCH] [COMPILER-RT] Fix CMake build for Apple/Darwin without Xcode and for universal build

[Kuba Brecka]

I was able to reproduce the CMake failure on 10.7, but I keep running into an unrelated issue (https://llvm.org/bugs/show_bug.cgi?id=23539) that prevents me from building compiler-rt successfully on 10.7.  The first part of the change (CMakeLists.txt) looks good to me, but could you add a comment explaining that "we unset the `${var}` if the return status is non-zero" or something similar?

For the second part (cmake/config-ix.cmake), is there a way to have the `if(APPLE)...` parts inside `test_target_arch`, as Alexey suggested?


REPOSITORY
  rL LLVM

http://reviews.llvm.org/D8936

EMAIL PREFERENCES
  http://reviews.llvm.org/settings/panel/emailpreferences/