logb
====

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

Gnulib module: logb

Portability problems fixed by Gnulib:

  * This function is missing a declaration on some platforms: Cygwin 1.5.x.

Portability problems not fixed by Gnulib:

  * This function is missing on some platforms: Minix 3.1.8.