Add touchf(), formatted version of touch()

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

src/Makefile.am

@@ -14,7 +14,7 @@ libite_la_SOURCES     = chomp.c		copyfile.c			\
 			reallocarray.c	rsync.c				\
 			strlcpy.c 	strlcat.c 	strtonum.c	\
 			strdupa.h	strndupa.h	strnlen.h	\
-			strmatch.c	systemf.c			\
+			strmatch.c	systemf.c	touchf.c	\
 			telnet.c	tempfile.c	truncatef.c	\
 			yorn.c		which.c				\
 			lite.h		strlite.h			\