Support Catalina for Mac (#3398)

diff --git a/bazel_configure.py b/bazel_configure.py
index ec254e5..02e67f1 100755
--- a/bazel_configure.py
+++ b/bazel_configure.py
@@ -191,7 +191,8 @@
 
   # on mac, /usr/bin/cpp --version returns this:
   #   Apple LLVM version 6.0 (clang-600.0.56) (based on LLVM 3.5svn)
-  mac_line = re.search('^(Apple LLVM version\s+[\d\.]+)\s+\(clang.*', first_line)
+  #   Apple clang version 11.0.0 (clang-1100.0.33.12)
+  mac_line = re.search('^(Apple (LLVM|clang) version\s+[\d\.]+)\s+\(clang.*', first_line)
   if mac_line:
     version = get_trailing_version(mac_line.group(1))
     if version: