9.43 atan2f

POSIX specification:
http://www.opengroup.org/onlinepubs/9699919799/functions/atan2f.html

Gnulib module: atan2f

Portability problems fixed by Gnulib:

• This function is missing on some platforms: Minix 3.1.8, AIX 5.1, Solaris 9.
• This function is only defined as a macro with arguments on some platforms: MSVC 9.

Portability problems not fixed by Gnulib: