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.

This used to be defined multiple times in different (but not all)
architectures. Moving it to general linux module since it's an
architecture independent feature.

Was able to move some of them up one level so they are valid on more
platforms with less duplication

These aren't exposed on non-MIPS musl targets, but since they're
part of a kernel API, they're still applicable, so we just don't
test them there but expose them anyways.

Note that termios2 doesn't exist on powerpc(64), termios
is used instead.

Signed-off-by: Tom Kirchner <tjk@amazon.com>
Signed-off-by: Ben Cressey <bcressey@amazon.com>

In addition, move the syscalls to the mips module file because they are
all identical in mips32 and mips64.

As a result of this commit, glob64_t will be added to mips64.

MINSIGSTKSZ is a minimum size of process stack allowed