Index: compiler-rt/trunk/cmake/config-ix.cmake
===================================================================
--- compiler-rt/trunk/cmake/config-ix.cmake
+++ compiler-rt/trunk/cmake/config-ix.cmake
@@ -217,7 +217,11 @@
       set(SANITIZER_MIN_OSX_VERSION 10.9)
     endif()
     if(SANITIZER_MIN_OSX_VERSION VERSION_LESS "10.7")
-      message(FATAL_ERROR "Too old OS X version: ${SANITIZER_MIN_OSX_VERSION}")
+      message(FATAL_ERROR "macOS deployment target '${SANITIZER_MIN_OSX_VERSION}' is too old.")
+    endif()
+    if(SANITIZER_MIN_OSX_VERSION VERSION_GREATER "10.9")
+      message(WARNING "macOS deployment target '${SANITIZER_MIN_OSX_VERSION}' is too new, setting to '10.9' instead.")
+      set(SANITIZER_MIN_OSX_VERSION 10.9)
     endif()
   endif()