Refactor PHP_PROG_BISON and PHP_PROG_RE2C

Refactor PHP_PROG_BISON and PHP_PROG_RE2C

This patch refactors these macros to also checks for the required given
versions of bison and re2c.

- PHP_PROG_RE2C and PHP_PROG_BISON take optional args - minmimum version
  required, and bison also excluded versions.
- Instead of caching values this uses manual checking and messaging
  outputs.
- It looks like the minimum version of RE2C 0.13.4 is working ok so far.

The genfiles script improvements:
- Add make override in genfiles
- Move checkings from makedist to genfiles
- Refactored output messages
- Various minor enhancements