* libc/include/sys/reent.h (_REENT_INIT_PTR): Fix macros
to handle latest on_exit change.
* libc/sys/linux/Makefile.am: Remove special compilation
for malloc.c and mcheck.c.
* libc/sys/linux/Makefile.in: Regenerated.
* libc/sys/linux/mntent.c: Add definition of _LIBC flag
after including <features.h>.
* libc/sys/linux/mcheck.c: Ditto.
* libc/sys/linux/malloc.c: Ditto plus define _GNU_SOURCE
for <features.h>.
* libc/sys/linux/intl/Makefile.am: Remove -D_LIBC and
add -DNOT_IN_libc to C flags.
* libc/sys/linux/intl/Makefile.in: Regenerated.
* libc/sys/linux/intl/config.h: Add definition of _LIBC.
* libc/sys/linux/linuxthreads/semaphore.h: Include
<bits/pthreadtypes.h>.
* libc/sys/linux/sys/dirent.h: Define _LIBC and NOT_IN_libc after
including <features.h>.
* libc/sys/linux/sys/lock.h: Ditto.
