Clang update script: support fetching pre-built CMake on Mac

tools/clang/scripts/update.sh

Index: tools/clang/scripts/update.sh
diff --git a/tools/clang/scripts/update.sh b/tools/clang/scripts/update.sh
index 10a46453221c46630e96be4cb96ff1ba843839db..32d2ead5a66b502c77b31f922c526ca8d6c25caa 100755
--- a/tools/clang/scripts/update.sh
+++ b/tools/clang/scripts/update.sh
@@ -190,14 +190,13 @@ if [[ -n ${LLVM_FORCE_HEAD_REVISION:-''} ]]; then
     fi
   fi
 
-  if [[ "${OS}" == "Linux" ]]; then
-    # TODO(hans): Might need to make this work on Mac eventually.
+  if [[ "${OS}" == "Linux" || "${OS}" == "Darwin" ]]; then
     if [[ $(cmake --version | grep -Eo '[0-9.]+') < "3.0" ]]; then
       # We need a newer CMake version.
       if [[ ! -e "${LLVM_BUILD_TOOLS_DIR}/cmake310" ]]; then
         echo "Downloading pre-built CMake 3.10..."
         mkdir -p "${LLVM_BUILD_TOOLS_DIR}"
-        curl --fail -L "${CDS_URL}/tools/cmake310.tgz" | \
+        curl --fail -L "${CDS_URL}/tools/cmake310_${OS}.tgz" | \
           tar zxf - -C "${LLVM_BUILD_TOOLS_DIR}"
         echo Done
       fi