9.21 acosl

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

Gnulib module: acosl

Portability problems fixed by Gnulib:

• This function is missing on some platforms: FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8, HP-UX 11, IRIX 6.5, Solaris 9, Cygwin, Interix 3.5, BeOS.
• This function is only defined as a macro with arguments on some platforms: MSVC 9.
• This function is not declared on some platforms: Mac OS X 10.3.

Portability problems not fixed by Gnulib: