* configure.host (sys_dir, newlib_cflags): Set sys_dir to tirtos and use
-D__DYNAMIC_REENT__ and -DMALLOC_PROVIDED compiler options for TIRTOS
target.
* libc/stdio/local.h (_STDIO_CLOSE_PER_REENT_STD_STREAMS): Change #ifdef
to not define this macro when __tirtos__ is defined.
* libc/sys/tirtos : Add support for TIRTOS.
* libc/sys/tirtos/Makefile.am, libc/sys/tirtos/lock.c: New files.
* libc/sys/tirtos/configure.in, libc/sys/tirtos/include/sys/lock.h: Ditto.