putc_unlocked
=============

POSIX specification:
 http://www.opengroup.org/onlinepubs/9699919799/functions/putc_unlocked.html

Gnulib module: ---

Portability problems fixed by Gnulib:

  * This function cannot be called from plain inline or extern inline functions on some platforms: OS X 10.8.

Portability problems not fixed by Gnulib:

  * This function is missing on some platforms: Minix 3.1.8, mingw, MSVC 9.

  * On some platforms, this function does not set errno or the stream error indicator on attempts to write to a read-only stream: Cygwin 1.7.9.