Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

WARNS=3'ify.

Repo copy libpthreads to libkse.
This introduces the WITHOUT_LIBKSE nob,
and changes WITHOUT_LIBPTHREADS to mean with neither threading libs.
Approved by: re(kensmith)

Increase the default stacksizes:

32-bit 64-bit
main thread 2MB 4MB
other threads 1MB 2MB

Allocate red zone and stack space together and then split red zone from
allocated space, orignal code left red zone unallocated, but those space
can be allocated by user code, and result was providing no protection.

Respect POSIX specification, a value return from pthread_attr_getguardsize
should be a value past to pthread_attr_setguardsize, not a rounded up value.
Also fix a stack size matching bug in thr_stack.c, now stack matching code
uses number of pages but not bytes length to match stack size, so for example,
size 512 bytes and size 513 bytes should both match 1 page stack size.

Reviewed by: deischen

Use mmap retuned value.

Reviewed by: deischen

Revamp libpthread so that it has a chance of working in an SMP
environment. This includes support for multiple KSEs and KSEGs.

The ability to create more than 1 KSE via pthread_setconcurrency()
is in the works as well as support for PTHREAD_SCOPE_SYSTEM threads.
Those should come shortly.

There are still some known issues which davidxu and I are working
on, but it'll make it easier for us by committing what we have.

This library now passes all of the ACE tests that libc_r passes
with the exception of one. It also seems to work OK with KDE
including konqueror, kwrite, etc. I haven't been able to get
mozilla to run due to lack of java plugin, so I'd be interested
to see how it works with that.

Reviewed by: davidxu

Make the changes needed for libpthread to compile in its new home.
The new libpthread will provide POSIX threading support using KSE.
These files were previously repo-copied from src/lib/libc_r.

Reviewed by: deischen
Approved by: -arch

Undo namespace pollution by prefixing the globals pthread_guard_default and
pthread_page_size.

Fix a bunch line wrapping.

Pointed out by: deischen

Don't use PAGE_SIZE in userland, instead use getpagesize(), this is to
allow running on other arches when the instructions are supported but
the page size granularity is not.

Glanced at by: peter

Make libc_r check the kern.usrstack sysctl instead of using internal
kernel #defines to figure out where the stack is located. This stops
libc_r from exploding when the kernel is compiled with a different
KVM size. IMHO this is all kinda bogus, it would be better to just
check %esp and work from that.

Implement pthread_attr_[gs]etguardsize(). Non-default-size stacks used to
be malloc()ed, but they are now allocated using mmap(), just as the
default-size stacks are. A separate cache of stacks is kept for
non-default-size stacks.

Collaboration with: deischen