Merge pull request #1875 from peternewman/0.10-c11-compat

Fix protoc version checking, since v20.x

config/ola.m4

@@ -44,7 +44,14 @@ if test -z "$PROTOC" ; then
   AC_MSG_ERROR([cannot find 'protoc' program]);
 elif test -n "$1" ; then
   AC_MSG_CHECKING([protoc version])
-  [protoc_version=`$PROTOC --version 2>&1 | grep 'libprotoc' | sed 's/.*\([0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\).*/\1/g'`]
+  # Since v20.x we only get effectively the minor and patch versions out of protoc.
+  # Treat them as major and minor and everything should keep working indefinitely.
+  # See https://protobuf.dev/support/version-support/
+  # So we've got either of these:
+  # libprotoc 2.4.1
+  # libprotoc 23.3
+  # The first sed ensures all versions have major, minor, patch, by adding a .0 on the end of ones missing it
+  [protoc_version=`$PROTOC --version 2>&1 | grep 'libprotoc' | sed 's/\([^\.0-9][0-9][0-9]*\.[0-9][0-9]*\)$/\1\.0/g' | sed 's/[^0-9]*\([0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\).*/\1/g'`]
   [required=$1]
   [required_major=`echo $required | sed 's/[^0-9].*//'`]
   [required_minor=`echo $required | sed 's/[0-9][0-9]*\.\([0-9][0-9]*\)\.[0-9][0-9]*/\1/'`]