Source release 17.1.0

third_party/protobuf/autogen.sh

@@ -30,8 +30,12 @@ set -ex
 
 # The absence of a m4 directory in googletest causes autoreconf to fail when
 # building under the CentOS docker image. It's a warning in regular build on
-# Ubuntu/gLinux as well.
-mkdir -p third_party/googletest/m4
+# Ubuntu/gLinux as well. (This is only needed if git submodules have been
+# initialized, which is typically only needed for testing; see the installation
+# instructions for details.)
+if test -d third_party/googletest; then
+  mkdir -p third_party/googletest/m4
+fi
 
 # TODO(kenton):  Remove the ",no-obsolete" part and fix the resulting warnings.
 autoreconf -f -i -Wall,no-obsolete