MFC r306349:
r306349 (by pfg):

hash(3): protect in-memory page when using cross-endianness.

When writing out pages in the "other endian" format, make a copy
instead of trashing the in-memory one.

Obtained from: NetBSD (CVS rev. 1.29)

MFC r287292:
Switch libc from using _sig{procmask,action,suspend} symbols, which
are aliases for the syscall stubs and are plt-interposed, to the
libc-private aliases of internally interposed sigprocmask() etc.

MFC r287300:
Use libthr interposed functions instead of syscalls, in posix_spawn()'
child.

MFC r287292:
Switch libc from using _sig{procmask,action,suspend} symbols, which
are aliases for the syscall stubs and are plt-interposed, to the
libc-private aliases of internally interposed sigprocmask() etc.

MFC r287300:
Use libthr interposed functions instead of syscalls, in posix_spawn()'
child.