x86: switch to generic old sigaction

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/x86/um/Kconfig b/arch/x86/um/Kconfig
index a372582..cf0f273 100644
--- a/arch/x86/um/Kconfig
+++ b/arch/x86/um/Kconfig
@@ -26,6 +26,7 @@
 	select MODULES_USE_ELF_REL
 	select CLONE_BACKWARDS
 	select OLD_SIGSUSPEND3
+	select OLD_SIGACTION
 
 config X86_64
 	def_bool 64BIT