this is commented out which forces c++11, but protobuf needs 17
--
--- a/configure.ac
+++ b/configure.ac
@@ -237,7 +237,7 @@
 # C++ version check
 
 # Check for C++17 support (optional)
-# AX_CXX_COMPILE_STDCXX(17, noext, optional)
+AX_CXX_COMPILE_STDCXX(17, noext, optional)
 
 if test "x$HAVE_CXX17" != "x1"; then
   # Check for C++11 support (optional)