K 10
svn:author
V 3
kib
K 8
svn:date
V 27
2016-02-12T07:38:19.835458Z
K 7
svn:log
V 781
POSIX states that #include <signal.h> shall make both mcontext_t and
ucontext_t available.  Our code even has XXX comment about this.

Add a bit of compliance by moving struct __ucontext definition into
sys/_ucontext.h and including it into signal.h and sys/ucontext.h.

Several machine/ucontext.h headers were changed to use namespace-safe
types (like uint64_t->__uint64_t) to not depend on sys/types.h.
struct __stack_t from sys/signal.h is made always visible in private
namespace to satisfy sys/_ucontext.h requirements.

Apparently mips _types.h pollutes global namespace with f_register_t
type definition.  This commit does not try to fix the issue.

PR:	207079
Reported and tested by:	Ting-Wei Lan <lantw44@gmail.com>
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks

END