Migrate to Postgres - Alias a Keyword?

We are migrating from Firebird to Postgres. We try to minimise changes required to the application code which has lots of SQLs in it. One of the incompatibilities between these two is the way to limit the number of rows returned by a SELECT query. 

In Postgres, SELECT * FROM TestTable LIMIT 10

In Firebird,   SELECT * FROM TestTable ROWS 10 

What I'm trying to do here is to get Postgres to accept ROWS as if it's LIMIT. Looks like this is possible by adding an alias in /src/include/parser/kwlist.h, although ROWS is already defined in it for other purpose. 

Does anyone has a suggestion on this? Can I achieve this without recompiling our own copy of Postgres?

Thanks

Huan