Move personality parser to a separate file

* personality.c: New file.
* Makefile.am (strace_SOURCES): Add it.
* system.c: Move sys_personality and related code to personality.c.
diff --git a/personality.c b/personality.c
new file mode 100644
index 0000000..a90d7dd
--- /dev/null
+++ b/personality.c
@@ -0,0 +1,13 @@
+#include "defs.h"
+
+#include <linux/personality.h>
+
+#include "xlat/personality_options.h"
+
+int
+sys_personality(struct tcb *tcp)
+{
+	if (entering(tcp))
+		printxval(personality_options, tcp->u_arg[0], "PER_???");
+	return 0;
+}