preparatory patch for -Wwrite-strings #2
diff --git a/util-linux/fbset.c b/util-linux/fbset.c
index 7ae0101..94d04b1 100644
--- a/util-linux/fbset.c
+++ b/util-linux/fbset.c
@@ -314,8 +314,8 @@
 {
 	struct fb_var_screeninfo var, varset;
 	int fh, i;
-	char *fbdev = DEFAULTFBDEV;
-	char *modefile = DEFAULTFBMODE;
+	const char *fbdev = DEFAULTFBDEV;
+	const char *modefile = DEFAULTFBMODE;
 	char *thisarg, *mode = NULL;
 
 	memset(&varset, 0xFF, sizeof(varset));
diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index 957316d..4a0e9f9 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -141,7 +141,8 @@
 				}
 				if (ENABLE_FEATURE_MDEV_EXEC && field == 3) {
 					// Command to run
-					char *s = "@$*", *s2;
+					const char *s = "@$*";
+					const char *s2;
 					s2 = strchr(s, *pos++);
 					if (!s2) {
 						// Force error
diff --git a/util-linux/switch_root.c b/util-linux/switch_root.c
index 4c23f69..007083b 100644
--- a/util-linux/switch_root.c
+++ b/util-linux/switch_root.c
@@ -28,7 +28,7 @@
 
 // Recursively delete contents of rootfs.
 
-static void delete_contents(char *directory)
+static void delete_contents(const char *directory)
 {
 	DIR *dir;
 	struct dirent *d;