more -Wall warning fixes from Cristian Ionescu-Idbohrn.

This time it resulted in small code changes:

function                                             old     new   delta
nexpr                                                820     828      +8
tail_main                                           1200    1202      +2
wrapf                                                166     167      +1
parse_mount_options                                  227     209     -18
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/1 up/down: 11/-18)             Total: -7 bytes

5 files changed, 23 insertions, 21 deletions

diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index 4fff20d..14aa593 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -120,8 +120,11 @@ static void make_device(char *path, int delete)
 
 				/* If not this device, skip rest of line */
 				/* (regexec returns whole pattern as "range" 0) */
-				if (result || off[0].rm_so || off[0].rm_eo != strlen(device_name))
+				if (result || off[0].rm_so
+				 || ((int)off[0].rm_eo != (int)strlen(device_name))
+				) {
 					goto next_line;
+				}
 			}
 
 			/* This line matches: stop parsing the file
diff --git a/util-linux/mount.c b/util-linux/mount.c
index 4b8aea8..292f877 100644
--- a/util-linux/mount.c
+++ b/util-linux/mount.c
@@ -307,7 +307,7 @@ static long parse_mount_options(char *options, char **unrecognized)
 
 	// Loop through options
 	for (;;) {
-		int i;
+		size_t i;
 		char *comma = strchr(options, ',');
 		const char *option_str = mount_option_str;
 
@@ -1004,7 +1004,7 @@ static int nfsmount(struct mntent *mp, long vfsflags, char *filteropts)
 			bb_herror_msg("%s", hostname);
 			goto fail;
 		}
-		if (hp->h_length > sizeof(struct in_addr)) {
+		if ((size_t)hp->h_length > sizeof(struct in_addr)) {
 			bb_error_msg("got bad hp->h_length");
 			hp->h_length = sizeof(struct in_addr);
 		}
@@ -1279,15 +1279,14 @@ static int nfsmount(struct mntent *mp, long vfsflags, char *filteropts)
 			if (hp == NULL) {
 				bb_herror_msg("%s", mounthost);
 				goto fail;
-			} else {
-				if (hp->h_length > sizeof(struct in_addr)) {
-					bb_error_msg("got bad hp->h_length?");
-					hp->h_length = sizeof(struct in_addr);
-				}
-				mount_server_addr.sin_family = AF_INET;
-				memcpy(&mount_server_addr.sin_addr,
-						hp->h_addr, hp->h_length);
 			}
+			if ((size_t)hp->h_length > sizeof(struct in_addr)) {
+				bb_error_msg("got bad hp->h_length");
+				hp->h_length = sizeof(struct in_addr);
+			}
+			mount_server_addr.sin_family = AF_INET;
+			memcpy(&mount_server_addr.sin_addr,
+						hp->h_addr, hp->h_length);
 		}
 	}
 
diff --git a/util-linux/switch_root.c b/util-linux/switch_root.c
index c030b99..bae695b 100644
--- a/util-linux/switch_root.c
+++ b/util-linux/switch_root.c
@@ -13,15 +13,15 @@
 // Make up for header deficiencies.
 
 #ifndef RAMFS_MAGIC
-#define RAMFS_MAGIC		0x858458f6
+#define RAMFS_MAGIC ((unsigned)0x858458f6)
 #endif
 
 #ifndef TMPFS_MAGIC
-#define TMPFS_MAGIC		0x01021994
+#define TMPFS_MAGIC ((unsigned)0x01021994)
 #endif
 
 #ifndef MS_MOVE
-#define MS_MOVE			8192
+#define MS_MOVE     8192
 #endif
 
 static dev_t rootdev;
@@ -91,10 +91,10 @@ int switch_root_main(int argc ATTRIBUTE_UNUSED, char **argv)
 	// we mean it.  (I could make this a CONFIG option, but I would get email
 	// from all the people who WILL eat their filesystems.)
 
-	if (lstat("/init", &st1) || !S_ISREG(st1.st_mode) || statfs("/", &stfs) ||
-		(stfs.f_type != RAMFS_MAGIC && stfs.f_type != TMPFS_MAGIC) ||
-		getpid() != 1)
-	{
+	if (lstat("/init", &st1) || !S_ISREG(st1.st_mode) || statfs("/", &stfs)
+	 || (((unsigned)stfs.f_type != RAMFS_MAGIC) && ((unsigned)stfs.f_type != TMPFS_MAGIC))
+	 || (getpid() != 1)
+	) {
 		bb_error_msg_and_die("not rootfs");
 	}
 
diff --git a/util-linux/volume_id/util.c b/util-linux/volume_id/util.c
index ce7de23..240b3c1 100644
--- a/util-linux/volume_id/util.c
+++ b/util-linux/volume_id/util.c
@@ -212,7 +212,7 @@ void *volume_id_get_buffer(struct volume_id *id, uint64_t off, size_t len)
 			}
 			dbg("got 0x%zx (%zi) bytes", buf_len, buf_len);
 			id->sbbuf_len = buf_len;
-			if (buf_len < off + len) {
+			if ((uint64_t)buf_len < off + len) {
 				dbg("requested 0x%zx bytes, got only 0x%zx bytes", len, buf_len);
 				return NULL;
 			}
@@ -243,7 +243,7 @@ void *volume_id_get_buffer(struct volume_id *id, uint64_t off, size_t len)
 		dbg("got 0x%zx (%zi) bytes", buf_len, buf_len);
 		id->seekbuf_off = off;
 		id->seekbuf_len = buf_len;
-		if (buf_len < len) {
+		if ((size_t)buf_len < len) {
 			dbg("requested 0x%zx bytes, got only 0x%zx bytes", len, buf_len);
 			return NULL;
 		}
diff --git a/util-linux/volume_id/volume_id.c b/util-linux/volume_id/volume_id.c
index de9aae2..aec96a2 100644
--- a/util-linux/volume_id/volume_id.c
+++ b/util-linux/volume_id/volume_id.c
@@ -152,7 +152,7 @@ static const probe_fptr fs2[] = {
 
 int volume_id_probe_all(struct volume_id *id, uint64_t off, uint64_t size)
 {
-	int i;
+	size_t i;
 
 	if (id == NULL)
 		return -EINVAL;