regexec
=======

POSIX specification:
 https://pubs.opengroup.org/onlinepubs/9699919799/functions/regexec.html

Gnulib module: regex

Portability problems fixed by Gnulib:

  * This function is missing on some platforms: mingw, MSVC 14.

  * Many regular expression implementations have bugs.

Portability problems not fixed by Gnulib: