* sysdeps/powerpc/tls.h (tcbhead_t): Add gscope_flag.
(THREAD_GSCOPE_FLAG_UNUSED, THREAD_GSCOPE_FLAG_USED,
THREAD_GSCOPE_FLAG_WAIT): Define.
(THREAD_GSCOPE_GET_FLAG, THREAD_GSCOPE_SET_FLAG,
THREAD_GSCOPE_RESET_FLAG, THREAD_GSCOPE_WAIT): Define.
* sysdeps/i386/tls.h (THREAD_GSCOPE_WAIT): Don't use
PTR_DEMANGLE.
(THREAD_GSCOPE_GET_FLAG): Define.
* sysdeps/x86_64/tls.h (THREAD_GSCOPE_GET_FLAG): Define.
* allocatestack.c (__wait_lookup_done): Use THREAD_GSCOPE_GET_FLAG
instead of ->header.gscope_flag directly.