+dnl RR_ is for obrender, OBT_ is for obt, keep major/minor in sync,
+dnl treat the rest separately.
+dnl
+dnl if MAJOR or MINOR version changes, be sure to change AC_INIT above to match.
+dnl the other variables aren't related to the user visible versions, but are used
+dnl to version the .so files.
+dnl if no backward compat is broken, it's just a preference if you want to bump
+dnl the AC_INIT micro version or minor version. if the AC_INIT micro version is
+dnl 0, don't write it out.
+dnl
+dnl How to process .so versioning,