getsubopt
=========

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

Gnulib module: getsubopt

Portability problems fixed by Gnulib:

  * This function is missing on some platforms: mingw, MSVC 14, Android 7.1.

  * This function is declared in unistd.h instead of stdlib.h on some platforms: Cygwin 1.7.1.

Portability problems not fixed by Gnulib: