configure.in: Test for __g77_integer...

        * configure.in: Test for __g77_integer, __g77_uinteger,
        __g77_longint, and __g77_ulongint builtin types, rather
        than mucking around with compiler headers.
        * configure: Regenerate.
        * g2c.hin (integer, logical, flag, ftnlen, ftnint): Use
        __g77_integer rather than autoconfigured value.
        (uinteger): Use __g77_uinteger rather than autoconfigured value.
        (longint): Use __g77_longint rather than autoconfigured value.
        (ulongint): Use __g77_ulongint rather than autoconfigured value.

From-SVN: r33990