Fix "format not a string literal" warning caused by tprintf(str)

* defs.h: Declare tprints().
* strace.c: Define tprints().
(tabto): Use tprints(str), since tprintf(str) was throwing a warning.
* desc.c: Use tprints(str) instead of tprintf("%s", str).
* file.c: Likewise.
* io.c: Likewise.
* net.c: Likewise.
* process.c: Likewise.
* signal.c: Likewise.
* syscall.c: Likewise.
* util.c: Likewise.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
diff --git a/io.c b/io.c
index e3cad66..fa51cef 100644
--- a/io.c
+++ b/io.c
@@ -426,7 +426,7 @@
 		tprintf(", ");
 		iop = ioctl_lookup(tcp->u_arg[1]);
 		if (iop) {
-			tprintf("%s", iop->symbol);
+			tprints(iop->symbol);
 			while ((iop = ioctl_next_match(iop)))
 				tprintf(" or %s", iop->symbol);
 		} else