Cleanup usr.sbin/fd* so they can compile under WARNS=6.

fdcontrol/fdcontrol.c:
	- Add const constraint to an intermediate value
	  which is not supposed to be changed elsewhere.
fdread/fdread.c:
	- Use _devname in favor of devname to avoid name
	  conflicit.
	- -1 is less than any positive number so in order
	  to get the block to function, we should get the
	  block a little earlier.
	- Cast to remove signed when we are sure that a
	  return value is positive, or is compared with
	  an positive number (tracknumber of a floppy
	  disk is not likely to have UINT_MAX/2 anyway)
fdread/fdutil.c:
	- Use more specific initializer
fdwrite/fdwrite.c:
	- Use static on format_track since it's not
	  referenced in other places.
	- Use const char* to represent string constant.

Bump WARNS accordingly.

2 files changed, 2 insertions, 2 deletions

diff --git a/usr.sbin/fdcontrol/Makefile b/usr.sbin/fdcontrol/Makefile
index 4696abd..e2b54aa 100644
--- a/usr.sbin/fdcontrol/Makefile
+++ b/usr.sbin/fdcontrol/Makefile
@@ -4,7 +4,7 @@
 
 PROG=	fdcontrol
 SRCS=	fdcontrol.c fdutil.c
-WARNS?=	2
+WARNS?=	6
 CFLAGS+= -I${.CURDIR}/../fdread
 MAN=	fdcontrol.8
 
diff --git a/usr.sbin/fdcontrol/fdcontrol.c b/usr.sbin/fdcontrol/fdcontrol.c
index ff0f90b..559ce02 100644
--- a/usr.sbin/fdcontrol/fdcontrol.c
+++ b/usr.sbin/fdcontrol/fdcontrol.c
@@ -157,7 +157,7 @@ mode = O_RDONLY | O_NONBLOCK;
 
 	if (showfmt) {
 		if (verbose) {
-			char *s;
+			const char *s;
 
 			printf("%s: %d KB media type\n", argv[0],
 			    (128 << ft.secsize) * ft.size / 1024);