8.82 unistd.h

POSIX specification:
http://www.opengroup.org/onlinepubs/9699919799/basedefs/unistd.h.html

Gnulib module: unistd

Portability problems fixed by Gnulib:

• This header file is missing on some platforms: MSVC 9.
• The SEEK_* macros are not defined in this file on some platforms: mingw.
• The *_FILENO macros are not defined in this file on some platforms: OS/2 EMX, mingw.
• The _exit function is not declared in this file on some platforms: mingw.
• Some platforms provide a NULL macro that cannot be used in arbitrary expressions: NetBSD 5.0

Portability problems not fixed by Gnulib: