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/Makefile.am b/Makefile.am
index a87f4a5..707f486 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -41,6 +41,7 @@
 	net.c		\
 	or1k_atomic.c	\
 	pathtrace.c	\
+	personality.c	\
 	process.c	\
 	ptp.c		\
 	quota.c		\