Build llvmCore with RTTI enabled.  <rdar://problem/10395761>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143714 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/buildit/build_llvm b/utils/buildit/build_llvm
index 0ffbc19..5aa3c2c 100755
--- a/utils/buildit/build_llvm
+++ b/utils/buildit/build_llvm
@@ -156,6 +156,7 @@
     UNIVERSAL_SDK_PATH=$SDKROOT \
     NO_RUNTIME_LIBS=1 \
     DISABLE_EDIS=1 \
+    REQUIRES_RTTI=1 \
     DEBUG_SYMBOLS=1 \
     LLVM_SUBMIT_VERSION=$LLVM_SUBMIT_VERSION \
     LLVM_SUBMIT_SUBVERSION=$LLVM_SUBMIT_SUBVERSION \