1.62: If 'VX' is given, realloc(foo,0) will bail, it shouldn't.
  1.61: Correctly call THREAD_UNLOCK() if the recursive call trap is sprung.
  1.58: Fixed style bugs (dot `.' at the end of error and warning messages).

Approved by:	phk, re (rwatson)

- Add a missing THREAD_UNLOCK()
- Remove allocation failure check from 'A' option, the 'X' option does
  this as a standalone check now.

just use _foo() <-- foo().  In the case of a libpthread that doesn't do
call conversion (such as linuxthreads and our upcoming libpthread), this
is adequate.  In the case of libc_r, we still need three names, which are
now _thread_sys_foo() <-- _foo() <-- foo().

Convert all internal libc usage of: aio_suspend(), close(), fsync(), msync(),
nanosleep(), open(), fcntl(), read(), and write() to _foo() instead of foo().

Remove all internal libc usage of: creat(), pause(), sleep(), system(),
tcdrain(), wait(), and waitpid().

Make thread cancellation fully POSIX-compliant.

Suggested by:	deischen

points.  For library functions, the pattern is __sleep() <--
_libc_sleep() <-- sleep().  The arrows represent weak aliases.  For
system calls, the pattern is _read() <-- _libc_read() <-- read().

Approved by:	phk

changes have made this too expensive.  This gains about 1.25% on
worldstone on my SMP machine.

Swap-less machines, for instance PicoBSDs, and machines which experience
page-out trafic, check with top(1), will probably want to reenable this
with:
	ln -s H /etc/malloc.conf

Suggested by: alc (&dyson ?)