[CMake] Workaround for the lipo output directory not being created.

This should resolve an issue reported by mclow.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@249158 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/cmake/Modules/CompilerRTDarwinUtils.cmake b/cmake/Modules/CompilerRTDarwinUtils.cmake
index 12969b9..9dc1c06 100644
--- a/cmake/Modules/CompilerRTDarwinUtils.cmake
+++ b/cmake/Modules/CompilerRTDarwinUtils.cmake
@@ -187,6 +187,7 @@
     "LIPO_FLAGS;DEPENDS"
     ${ARGN})
   add_custom_command(OUTPUT ${LIB_OUTPUT_DIR}/lib${name}.a
+    COMMAND ${CMAKE_COMMAND} -E make_directory ${LIB_OUTPUT_DIR}
     COMMAND lipo -output
             ${LIB_OUTPUT_DIR}/lib${name}.a
             -create ${LIB_LIPO_FLAGS}