generic sys_compat_rt_sigaction()

Again, protected by a temporary config symbol (GENERIC_COMPAT_RT_SIGACTION);
will be gone by the end of series.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/Kconfig b/arch/Kconfig
index 6b1df95..3b4a416 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -368,6 +368,9 @@
 config GENERIC_COMPAT_RT_SIGQUEUEINFO
 	bool
 
+config GENERIC_COMPAT_RT_SIGACTION
+	bool
+
 #
 # ABI hall of shame
 #