These are defined in the fcntl.h glibc header on MIPS systems
on Linux but missing in the libc crate, so add them as they are
required for the file locking API in rustc.

separate for gnu and msvc


scope resolve c_int

these types are not allowed, and more scope resolution


use size_t

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

Discovered while debugging: djg/audioipc-2#52

These errno's are defined in <sys/errno.h> on DragonFlyBSD.

Signed-off-by: Levente Kurusa <lkurusa@acm.org>

Signed-off-by: Gerd Zellweger <gzellweger@vmware.com>