Implement _Exit(3).

Change-Id: Ida6ac844cc87d38c9645b197dd8188bb73e27dbe

Conflicts:
	libc/SYSCALLS.TXT
	libc/arch-arm64/syscalls/_exit.S
	libc/arch-mips/syscalls/_exit.S
	libc/arch-mips64/syscalls/_exit.S
	libc/arch-x86_64/syscalls/_exit.S
	tests/unistd_test.cpp
Fix build: include what you use.

Change-Id: I12b2d5e434ad3ed38d4451bd470673781e6ca8fe
Flesh out <locale.h>.

This is a trivial implementation that only supports the C/POSIX locale.

Change-Id: Ib11cea4249e1862aca96a8b94d58ea9a418cbe75

Conflicts:
	libc/bionic/locale.cpp
	libc/include/locale.h
	tests/locale_test.cpp
Use glibc structure for __cmsg_nxthdr.

Bug: 13418328
Change-Id: I7e656b373e53e80d708325321e48dcedacf5086d

Conflicts:
	libc/Android.mk
	libc/include/sys/socket.h
Use the glibc name user_fpregs_struct.

Instead of the kernel name user_i387_struct.

Bug: 13889008
Change-Id: Ideec2e1ce36c1faa4b5b2db1999ad2b23757ca4d
Improve the <sstream> test.

It looks like libcxx's testing is crap too, and this turned up
another bug in stlport.

Change-Id: I98c93dceaa8225c3cc280166d4bb74adaf94a324

Conflicts:
	tests/sstream_test.cpp
Replace the bionic hack for a vfprintf leak with (roughly) the upstream fix.

Currently in bionic free and freedtoa are equivalent, but that's not true
of gdtoa. This makes it easier to test gdtoa without having to replace
everything. (Yes, I found this bug the hard way.)

Change-Id: I290823a2a0a83329def5f2719b349215ad0dbbde

Conflicts:
	libc/stdio/vfprintf.c