diff --git a/tools/objc/libtool.sh b/tools/objc/libtool.sh
index 5b050a18c59546..d0a6882a46558b 100755
--- a/tools/objc/libtool.sh
+++ b/tools/objc/libtool.sh
@@ -37,7 +37,9 @@ WRAPPER="${MY_LOCATION}/xcrunwrapper.sh"
 # Ensure 0 timestamping for hermetic results.
 export ZERO_AR_DATE=1
 
-if "${MY_LOCATION}"/libtool_check_unique "$@"; then
+if [ ! -f "${MY_LOCATION}"/libtool_check_unique ] ; then
+    echo "libtool_check_unique not found. Please file an issue at github.com/bazelbuild/bazel"
+elif "${MY_LOCATION}"/libtool_check_unique "$@"; then
   # If there are no duplicate .o basenames,
   # libtool can be invoked with the original arguments.
   "${WRAPPER}" libtool "$@"
diff --git a/tools/osx/crosstool/BUILD.tpl b/tools/osx/crosstool/BUILD.tpl
index dcd7002b7ac235..5342f4ac9b5622 100644
--- a/tools/osx/crosstool/BUILD.tpl
+++ b/tools/osx/crosstool/BUILD.tpl
@@ -50,6 +50,7 @@ cc_toolchain_suite(
             ":builtin_include_directory_paths",
             ":cc_wrapper",
             ":libtool",
+            ":libtool_check_unique",
             ":make_hashed_objlist.py",
             ":wrapped_clang",
             ":wrapped_clang_pp",