fesetenv
========

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

Gnulib module: fenv-environment

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, AIX 5.1, IRIX 6.5, Solaris 9, Cygwin 1.7.7, MSVC 9, Android 4.4.

  * This function does not work on some platforms: FreeBSD 12.2/arm64.

  * This function does not restore the floating-point exception trap bits on some platforms: musl libc/i386, musl libc/x86_64, AIX 7.3, Solaris 10 and 11, MSVC 14.

  * The macro FE_DFL_ENV cannot be used because it leads to a link error on some platforms: NetBSD 9.3/hppa, NetBSD 9.3/sparc, Cygwin 2.9.0.

  * This function, when called with FE_DFL_ENV argument, has no effect on the x86 mxcsr register and thus on floating-point operations performed in the SSE unit on some platforms: mingw 10.

Portability problems not fixed by Gnulib: