diff --git a/compiler-rt/cmake/Modules/CompilerRTDarwinUtils.cmake b/compiler-rt/cmake/Modules/CompilerRTDarwinUtils.cmake
--- a/compiler-rt/cmake/Modules/CompilerRTDarwinUtils.cmake
+++ b/compiler-rt/cmake/Modules/CompilerRTDarwinUtils.cmake
@@ -70,8 +70,10 @@
     )
   endif()
   if(NOT result_process EQUAL 0)
-    message(FATAL_ERROR
+    message(WARNING
       "Failed to determine SDK version for \"${sdk_name}\" SDK")
+    set(${var} "0" PARENT_SCOPE)
+    return()
   endif()
   # Check reported version looks sane.
   if (NOT "${var_internal}" MATCHES "^[0-9]+\\.[0-9]+(\\.[0-9]+)?$")