[klibc] sigsuspend: unbreak s390x

s390 does *not* work with RT syscalls, and s390x is distinguished
from s390 even if they share the same arch include directory

tested both on zelenka.debian.org

Signed-off-by: Thorsten Glaser <tg@mirbsd.org>
Signed-off-by: maximilian attems <max@stro.at>
diff --git a/usr/klibc/SYSCALLS.def b/usr/klibc/SYSCALLS.def
index 872acbf..70838b8 100644
--- a/usr/klibc/SYSCALLS.def
+++ b/usr/klibc/SYSCALLS.def
@@ -218,7 +218,7 @@
  * The arguments other than the sigset_t are assumed ignored.
  */
 <cris,sh,sparc,alpha,ppc,sparc64> int sigsuspend::__sigsuspend_s(sigset_t);
-<arm,frv,i386,m68k,mn10300,s390> int sigsuspend::__sigsuspend_xxs(int, int, sigset_t);
+<arm,frv,i386,m68k,mn10300,s390,s390x> int sigsuspend::__sigsuspend_xxs(int, int, sigset_t);
 #endif
 int kill(pid_t, int);
 <?> unsigned int alarm(unsigned int);