On OS X 10.11 System Integrity Protection prevents the DYLD environment variables from being set on system binaries. To work around this r276710 accepts DYLD_LIBRARY_PATH as a CMake variable and sets it directly on the archiver commands.

To make this work with bootstrapping we need to set DYLD_LIBRARY_PATH to the current stage's library directory and pass that into the next stage's configuration.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@276711 91177308-0d34-0410-b5e6-96231b3b80d8