build: fix unused/uninitialized variable warnings

Fix a few warnings about unused and uninitialized variables.

Also fix util/subst.c to include <sys/time.h> to avoid using
undeclared functions gettimeofday() and futimes().

Signed-off-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/debugfs/debugfs.c b/debugfs/debugfs.c
index b41626c..b6ba1da 100644
--- a/debugfs/debugfs.c
+++ b/debugfs/debugfs.c
@@ -2347,7 +2347,6 @@
 
 void do_dump_mmp(int argc EXT2FS_ATTR((unused)), char *argv[])
 {
-	struct ext2_super_block *sb;
 	struct mmp_struct *mmp_s;
 	time_t t;
 	errcode_t retval = 0;
@@ -2355,8 +2354,6 @@
 	if (check_fs_open(argv[0]))
 		return;
 
-	sb  = current_fs->super;
-
 	if (current_fs->mmp_buf == NULL) {
 		retval = ext2fs_get_mem(current_fs->blocksize,
 					&current_fs->mmp_buf);
diff --git a/e2fsck/pass5.c b/e2fsck/pass5.c
index b31490f..d0b1ced 100644
--- a/e2fsck/pass5.c
+++ b/e2fsck/pass5.c
@@ -206,7 +206,6 @@
 	problem_t	problem, save_problem;
 	int		fixit, had_problem;
 	errcode_t	retval;
-	int		csum_flag;
 	int	old_desc_blocks = 0;
 	int	count = 0;
 	int	cmp_block = 0;
@@ -253,8 +252,6 @@
 		goto errout;
 	}
 
-	csum_flag = EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
-					       EXT4_FEATURE_RO_COMPAT_GDT_CSUM);
 redo_counts:
 	had_problem = 0;
 	save_problem = 0;
diff --git a/lib/ext2fs/blkmap64_rb.c b/lib/ext2fs/blkmap64_rb.c
index 4dcb03f..a1dde6d 100644
--- a/lib/ext2fs/blkmap64_rb.c
+++ b/lib/ext2fs/blkmap64_rb.c
@@ -83,7 +83,7 @@
 
 static void check_tree(struct rb_root *root, const char *msg)
 {
-	struct rb_node *new_node, *node, *next;
+	struct rb_node *node;
 	struct bmap_rb_extent *ext, *old = NULL;
 
 	for (node = ext2fs_rb_first(root); node;
diff --git a/lib/quota/mkquota.c b/lib/quota/mkquota.c
index 58803d0..0ece088 100644
--- a/lib/quota/mkquota.c
+++ b/lib/quota/mkquota.c
@@ -580,7 +580,6 @@
 errcode_t quota_compare_and_update(quota_ctx_t qctx, int qtype,
 				   int *usage_inconsistent)
 {
-	ext2_filsys fs = qctx->fs;
 	struct quota_handle qh;
 	struct scan_dquots_data scan_data;
 	struct dquot *dq;
diff --git a/misc/mk_hugefiles.c b/misc/mk_hugefiles.c
index 6bc25e6..7f1be2e 100644
--- a/misc/mk_hugefiles.c
+++ b/misc/mk_hugefiles.c
@@ -468,7 +468,7 @@
 	unsigned long	i;
 	ext2_ino_t	dir;
 	errcode_t	retval;
-	blk64_t		fs_blocks, part_offset;
+	blk64_t		fs_blocks, part_offset = 0;
 	unsigned long	align;
 	int		d, dsize;
 	char		*t;
diff --git a/util/subst.c b/util/subst.c
index 6244831..36eaa94 100644
--- a/util/subst.c
+++ b/util/subst.c
@@ -14,6 +14,9 @@
 #include <unistd.h>
 #include <string.h>
 #include <ctype.h>
+#ifdef HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>