Bump minimum re2c version to 0.13.7

Closes GH-6516.

Author: cmb69

configure.ac

@@ -154,7 +154,7 @@ PHP_RUNPATH_SWITCH
 dnl Checks for some support/generator progs.
 PHP_PROG_AWK
 PHP_PROG_BISON([3.0.0])
-PHP_PROG_RE2C([0.13.4])
+PHP_PROG_RE2C([0.13.7])
 
 PHP_ARG_ENABLE([re2c-cgoto],
   [whether to enable computed goto gcc extension with re2c],