[sanitizer] Passthrough CMAKE_OSX_DEPLOYMENT_TARGET when building compiler-rt from clang/runtime/CMakeLists.txt
[sanitizer] Passthrough CMAKE_OSX_DEPLOYMENT_TARGET when building compiler-rt from clang/runtime/CMakeLists.txt

This breaks some Swift builds, because Swift's build scripts explicitly set CMAKE_OSX_DEPLOYMENT_TARGET. This however isn't propagated to the compiler-rt build, causing build errors.

Differential Revision: https://reviews.llvm.org/D26558



git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@286898 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang