Move statfs related parsers to a separate file

* statfs.c: New file.
* Makefile.am (strace_SOURCES): Add it.
* file.c (sprintfstype, printstatfs, sys_statfs, sys_fstatfs): Move
to statfs.c.
[HAVE_STATFS64] (printstatfs64, printcompat_statfs64, sys_statfs64,
sys_fstatfs64): Likewise.
[ALPHA] (osf_statfs, osf_fstatfs): Likewise.
diff --git a/Makefile.am b/Makefile.am
index a84375d..b76c979 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -47,6 +47,7 @@
 	signal.c	\
 	sock.c		\
 	socketutils.c	\
+	statfs.c	\
 	strace.c	\
 	stream.c	\
 	syscall.c	\