This patch removes use of the obsolete INTDEF/INTUSE mechanism for
__cxa_atexit, replacing it with libc_hidden_def/libc_hidden_proto.
Tested for x86_64 that installed stripped shared libraries are
unchanged by the patch.
[BZ #14132]
* stdlib/cxa_atexit.c (__cxa_atexit): Use libc_hidden_def instead
of INTDEF.
* include/stdlib.h (__cxa_atexit_internal): Remove declaration.
(__cxa_atexit): Use libc_hidden_proto.
[!NOT_IN_libc] (__cxa_atexit): Remove macro definition.