Index: cddl/contrib/opensolaris/cmd/zfs/zfs_main.c
===================================================================
--- cddl/contrib/opensolaris/cmd/zfs/zfs_main.c
+++ cddl/contrib/opensolaris/cmd/zfs/zfs_main.c
@@ -7151,7 +7151,7 @@
 zfs_do_channel_program(int argc, char **argv)
 {
 	int ret, fd;
-	char c;
+	int c;
 	char *progbuf, *filename, *poolname;
 	size_t progsize, progread;
 	nvlist_t *outnvl;
Index: cddl/contrib/opensolaris/cmd/zhack/zhack.c
===================================================================
--- cddl/contrib/opensolaris/cmd/zhack/zhack.c
+++ cddl/contrib/opensolaris/cmd/zhack/zhack.c
@@ -300,7 +300,7 @@
 static void
 zhack_do_feature_enable(int argc, char **argv)
 {
-	char c;
+	int c;
 	char *desc, *target;
 	spa_t *spa;
 	objset_t *mos;
@@ -395,7 +395,7 @@
 static void
 zhack_do_feature_ref(int argc, char **argv)
 {
-	char c;
+	int c;
 	char *target;
 	boolean_t decr = B_FALSE;
 	spa_t *spa;
@@ -515,7 +515,7 @@
 	char *path[MAX_NUM_PATHS];
 	const char *subcommand;
 	int rv = 0;
-	char c;
+	int c;
 
 	g_importargs.path = path;
 
Index: cddl/contrib/opensolaris/cmd/zpool/zpool_main.c
===================================================================
--- cddl/contrib/opensolaris/cmd/zpool/zpool_main.c
+++ cddl/contrib/opensolaris/cmd/zpool/zpool_main.c
@@ -633,7 +633,7 @@
 	boolean_t stop = B_FALSE;
 	boolean_t noop = B_FALSE;
 	boolean_t parsable = B_FALSE;
-	char c;
+	int c;
 
 	/* check options */
 	while ((c = getopt(argc, argv, "nps")) != -1) {
Index: cddl/contrib/opensolaris/cmd/zstreamdump/zstreamdump.c
===================================================================
--- cddl/contrib/opensolaris/cmd/zstreamdump/zstreamdump.c
+++ cddl/contrib/opensolaris/cmd/zstreamdump/zstreamdump.c
@@ -214,7 +214,7 @@
 	struct drr_spill *drrs = &thedrr.drr_u.drr_spill;
 	struct drr_write_embedded *drrwe = &thedrr.drr_u.drr_write_embedded;
 	struct drr_checksum *drrc = &thedrr.drr_u.drr_checksum;
-	char c;
+	int c;
 	boolean_t verbose = B_FALSE;
 	boolean_t very_verbose = B_FALSE;
 	boolean_t first = B_TRUE;
Index: tests/sys/cddl/zfs/bin/mkfile.c
===================================================================
--- tests/sys/cddl/zfs/bin/mkfile.c
+++ tests/sys/cddl/zfs/bin/mkfile.c
@@ -170,7 +170,7 @@
 main(int argc, char *argv[])
 {
 	unsigned long long fsize;
-	char ch;
+	int ch;
 
 	/* We have at least 2 arguments. */
 	if (argc < 3) {