include: Remove ___CLIENTSIGNALALL_DEFINED___ copypasta

___CLIENTSIGNAL_DEFINED___ is a hack to work around the declaration of
ClientSignal both in our own headers and in <X11/include/fontproto.h>,
the latter of which is properly part of libXfont (1, only) but packaged
in xorgproto because we have made some mistakes. ClientSignalAll needs
no such workaround.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
1 job for fontproto in 5 minutes and 26 seconds (queued for 1 minute and 47 seconds)
Status Job ID Name Coverage
  Test
passed #35009
job

00:05:26