3 files changed, 6 insertions, 4 deletions
diff --git a/usr.bin/compress/Makefile b/usr.bin/compress/Makefile
index 0f6f5ddab9ce..02f7fbbd8810 100644
--- a/usr.bin/compress/Makefile
+++ b/usr.bin/compress/Makefile
@@ -1,6 +1,7 @@
 #	@(#)Makefile	8.2 (Berkeley) 4/17/94
 
 PROG=	compress
+CFLAGS+=-Wall
 SRCS=	compress.c zopen.c
 LINKS=	${BINDIR}/compress ${BINDIR}/uncompress
 MLINKS=	compress.1 uncompress.1
diff --git a/usr.bin/compress/compress.c b/usr.bin/compress/compress.c
index 5e323d3bde13..e81963527cbd 100644
--- a/usr.bin/compress/compress.c
+++ b/usr.bin/compress/compress.c
@@ -32,13 +32,13 @@
  */
 
 #ifndef lint
-static char copyright[] =
+static const char copyright[] =
 "@(#) Copyright (c) 1992, 1993\n\
 	The Regents of the University of California.  All rights reserved.\n";
 #endif /* not lint */
 
 #ifndef lint
-static char sccsid[] = "@(#)compress.c	8.2 (Berkeley) 1/7/94";
+static const char sccsid[] = "@(#)compress.c	8.2 (Berkeley) 1/7/94";
 #endif /* not lint */
 
 #include <sys/param.h>
diff --git a/usr.bin/compress/zopen.c b/usr.bin/compress/zopen.c
index 5e5357b74b9e..abe31f2de63f 100644
--- a/usr.bin/compress/zopen.c
+++ b/usr.bin/compress/zopen.c
@@ -388,7 +388,7 @@ output(zs, ocode)
 		 * Since ocode is always >= 8 bits, only need to mask the first
 		 * hunk on the left.
 		 */
-		*bp = (*bp & rmask[r_off]) | (ocode << r_off) & lmask[r_off];
+		*bp = (*bp & rmask[r_off]) | ((ocode << r_off) & lmask[r_off]);
 		bp++;
 		bits -= (8 - r_off);
 		ocode >>= 8 - r_off;
@@ -698,7 +698,7 @@ zopen(fname, mode, bits)
 {
 	struct s_zstate *zs;
 
-	if (mode[0] != 'r' && mode[0] != 'w' || mode[1] != '\0' ||
+	if ((mode[0] != 'r' && mode[0] != 'w') || mode[1] != '\0' ||
 	    bits < 0 || bits > BITS) {
 		errno = EINVAL;
 		return (NULL);
@@ -738,4 +738,5 @@ zopen(fname, mode, bits)
 		return (funopen(zs, NULL, zwrite, NULL, zclose));
 	}
 	/* NOTREACHED */
+	return (NULL);
 }