Fix a syntax error which resulted in update.sh always using the old Clang.

tools/clang/scripts/update.sh

 #!/usr/bin/env bash
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This script will check out llvm and clang into third_party/llvm and build it.
 
 # Do NOT CHANGE this if you don't know what you're doing -- see
 # https://code.google.com/p/chromium/wiki/UpdatingClang
 # Reverting problematic clang rolls is safe, though.
@@ skipping 18 matching lines @@
 set -e
 
 OS="$(uname -s)"
 
 # Parse command line options.
 force_local_build=
 mac_only=
 run_tests=
 bootstrap=
 with_android=yes
-is_asan_mac_builder=
+# Temporary workaround for http://crbug.com/170629: use older Clang for ASan
+# Mac builders.
+is_asan_mac_builder_hackfix=
 with_tools_extra=
 if [[ "${OS}" = "Darwin" ]]; then
   with_android=
 fi
 
 while [[ $# > 0 ]]; do
   case $1 in
     --bootstrap)
       bootstrap=yes
       ;;
     --force-local-build)
       force_local_build=yes
       ;;
     --mac-only)
       mac_only=yes
       ;;
     --run-tests)
       run_tests=yes
       ;;
     --without-android)
       with_android=
       ;;
-    --is-asan-mac-builder)
-      is_asan_mac_builder=yes
+    # Temporary workaround for http://crbug.com/170629 - use older Clang for
+    # ASan Mac builders.
+    --is-asan-mac-builder-hackfix)
+      is_asan_mac_builder_hackfix=yes
       ;;
     --with-tools-extra)
       with_tools_extra=yes
       ;;
     --help)
       echo "usage: $0 [--force-local-build] [--mac-only] [--run-tests] "
       echo "--bootstrap: First build clang with CC, then with itself."
       echo "--force-local-build: Don't try to download prebuilt binaries."
       echo "--mac-only: Do initial download only on Mac systems."
       echo "--run-tests: Run tests after building. Only for local builds."
       echo "--without-android: Don't build ASan Android runtime library."
-      echo "--is-asan-mac-builder: Use older Clang to build ASan on Mac."
+      echo "--is-asan-mac-builder-hackfix: Use older Clang" \
+           "to build ASan on Mac."
       echo "--with-tools-extra: Also build the clang-tools-extra repository."
       exit 1
       ;;
   esac
   shift
 done
 
 # Are we on a Chrome buildbot running ASan?
 function on_asan_mac_host {
   HOST="$(uname -n)"
   # Chrome Mac ASan Builder.
   if [[ "${HOST}" == "vm633-m1.golo.chromium.org" ]]; then
     return 0
   fi
   # Chrome Mac ASan LKGR.
   if [[ "${HOST}" == "mini11-a1.golo.chromium.org" ]]; then
     return 0
   fi
   # mac_asan trybots.
   for num in $(seq 600 655)
   do
     if [[ "${HOST}" == "vm${num}-m4.golo.chromium.org" ]]; then
       return 0
     fi
   done
   return 1
 }
 
 # Use older Clang for ASan Mac builds. See http://crbug.com/170629.
-if [[ -n is_asan_mac_builder ]] || on_asan_mac_host; then
+if [[ -n "${is_asan_mac_builder_hackfix}" ]] || on_asan_mac_host; then
   CLANG_REVISION=${CLANG_ASAN_MAC_REVISION}
 fi
 
 # --mac-only prevents the initial download on non-mac systems, but if clang has
 # already been downloaded in the past, this script keeps it up to date even if
 # --mac-only is passed in and the system isn't a mac. People who don't like this
 # can just delete their third_party/llvm-build directory.
 if [[ -n "$mac_only" ]] && [[ "${OS}" != "Darwin" ]] &&
     [[ ! ( "$GYP_DEFINES" =~ .*(clang|tsan|asan)=1.* ) ]] &&
     ! [[ -d "${LLVM_BUILD_DIR}" ]]; then
@@ skipping 266 matching lines @@
   # Run a few tests.
   PLUGIN_SRC_DIR="${THIS_DIR}/../plugins"
   "${PLUGIN_SRC_DIR}/tests/test.sh" "${LLVM_BUILD_DIR}/Release+Asserts"
   cd "${LLVM_BUILD_DIR}"
   make check-all
   cd -
 fi
 
 # After everything is done, log success for this revision.
 echo "${CLANG_REVISION}" > "${STAMP_FILE}"