Add clang-tblgen to OPTIONAL_DIRS when building native tools for the

cross build, so that a native version of clang-tblgen is available.
Should unbreak Clang cross build.

Also disable Polly for the native tool build, since it depends on
external libraries which may not be available, and it isn't required
anyway.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141454 91177308-0d34-0410-b5e6-96231b3b80d8

Makefile

@@ -28,7 +28,7 @@ ifneq ($(findstring llvmCore, $(RC_ProjectName)),llvmCore)  # Normal build (not
 
 ifeq ($(BUILD_DIRS_ONLY),1)
   DIRS := lib/Support lib/TableGen utils
-  OPTIONAL_DIRS :=
+  OPTIONAL_DIRS := tools/clang/utils/TableGen
 else
   DIRS := lib/Support lib/TableGen utils lib/VMCore lib tools/llvm-shlib \
           tools/llvm-config tools runtime docs unittests
@@ -118,7 +118,8 @@ cross-compile-build-tools:
 	  unset CFLAGS ; \
 	  unset CXXFLAGS ; \
 	  $(PROJ_SRC_DIR)/configure --build=$(BUILD_TRIPLE) \
-		--host=$(BUILD_TRIPLE) --target=$(BUILD_TRIPLE); \
+		--host=$(BUILD_TRIPLE) --target=$(BUILD_TRIPLE) \
+	        --disable-polly ; \
 	  cd .. ; \
 	fi; \
 	(unset SDKROOT; \