* sysdeps/unix/sysv/linux/x86_64/pthread_once.S: Fix many
leftovers from the ia32 code.
* sysdeps/unix/sysv/linux/i386/pthread_once.S: Remove unneccessary
memory load.
(clear_once_control): Don't load %esi.
* sysdeps/x86_64/tls.h: Remove all traces of segment descriptor
handling.
* sysdeps/unix/sysv/linux/x86_64/fork.c: New file.
* sysdeps/x86_64/tls.h: Remove unnecessary macros, left over from x86.
(TLS_GET_FS): New #define.
(TLS_SET_FS): New #define.
Correct value of __NR_set_thread_area.
* malloc/hooks.c [_LIBC && (USE___THREAD || (USE_TLS && !SHARED))]
(malloc_starter, memalign_starter, free_starter): Don't define these.
* malloc/malloc.c [_LIBC && (USE___THREAD || (USE_TLS && !SHARED))]:
Don't declare them either.
* malloc/arena.c (ptmalloc_init) [_LIBC && USE_TLS]: Don't call
__pthread_initialize, so no need to set hooks to *_starter.
(ptmalloc_init_minimal): New function, broken out of ptmalloc_init.
[_LIBC && SHARED && USE_TLS && !USE___THREAD]
(__libc_malloc_pthread_startup): New function.
* malloc/Versions (libc: GLIBC_PRIVATE): New set, add that function.
* malloc/hooks.c (memalign_starter): New function.
* malloc/malloc.c: Declare it.
* malloc/arena.c (save_memalign_hook): New variable.
(ptmalloc_init): Set __memalign_hook to memalign_starter.
* elf/dl-minimal.c (free): Clear the memory.
(calloc): Just call malloc, knowing all memory it returns is cleared.
* sysdeps/generic/dl-tls.c (allocate_dtv): Use calloc instead of
malloc and memset; calloc can avoid the zeroing when redundant.
(_dl_tls_setup): Likewise.
* elf/dl-load.c (decompose_rpath): Likewise.
* sysdeps/generic/libc-tls.c (__libc_setup_tls): Comment out memset
call, since memory from sbrk at startup is already zero.
* elf/rtld.c (_dl_start, dl_main): TLS_INIT_TP macro now returns an
error string for failure, null for success. Update callers.
* sysdeps/generic/libc-tls.c (__libc_setup_tls): Likewise.
* elf/dl-load.c (_dl_map_object_from_fd): Likewise.
