[klibc] Use RT signal system calls on MIPS

The old signal system calls seem rather messed up on MIPS, but the
headers should be clean for the RT signals, so just use those.

Reported-by: Thorsten Glaser <tg@mirbsd.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/usr/include/arch/mips/klibc/archconfig.h b/usr/include/arch/mips/klibc/archconfig.h
index ff0afb5..9c21efc 100644
--- a/usr/include/arch/mips/klibc/archconfig.h
+++ b/usr/include/arch/mips/klibc/archconfig.h
@@ -18,4 +18,7 @@
 /* MIPS has nonstandard socket definitions */
 #define _KLIBC_HAS_ARCHSOCKET_H 1
 
+/* We can use RT signals on MIPS */
+#define _KLIBC_USE_RT_SIG 1
+
 #endif				/* _KLIBC_ARCHCONFIG_H */
diff --git a/usr/include/arch/mips64/klibc/archconfig.h b/usr/include/arch/mips64/klibc/archconfig.h
index 9071cb4..4d856a5 100644
--- a/usr/include/arch/mips64/klibc/archconfig.h
+++ b/usr/include/arch/mips64/klibc/archconfig.h
@@ -12,4 +12,7 @@
 /* MIPS has nonstandard socket definitions */
 #define _KLIBC_HAS_ARCHSOCKET_H 1
 
+/* We can use RT signals on MIPS */
+#define _KLIBC_USE_RT_SIG 1
+
 #endif				/* _KLIBC_ARCHCONFIG_H */