Ten conformtest failures arise from the internal header
include/bits/ipc.h failing to condition internal declarations, outside
the public namespace of headers including bits/ipc.h, on [!_ISOMAC].
As discussed in
<https://sourceware.org/ml/libc-alpha/2015-06/msg00653.html>, the
internal declarations that are actually relevant are in ipc_priv.h and
so include/bits/ipc.h should not be needed at all; this patch removes
it. (Ten further conformtest failures for other headers including
bits/ipc.h remain because of other conformance issues in those
headers.)
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).