process.c: move exit parser to a separate file

* exit.c: New file.
* Makefile.am (strace_SOURCES): Add it.
* process.c (sys_exit): Move to exit.c.
diff --git a/exit.c b/exit.c
new file mode 100644
index 0000000..0e0c2ea
--- /dev/null
+++ b/exit.c
@@ -0,0 +1,16 @@
+#include "defs.h"
+
+int
+sys_exit(struct tcb *tcp)
+{
+	if (exiting(tcp)) {
+		fprintf(stderr, "_exit returned!\n");
+		return -1;
+	}
+	/* special case: we stop tracing this process, finish line now */
+	tprintf("%ld) ", tcp->u_arg[0]);
+	tabto();
+	tprints("= ?\n");
+	line_ended();
+	return 0;
+}