Avoid gcc warnings about infinite loop.

This seemingly redundant change avoids a gcc warning/error:

  error: cannot optimize possibly infinite loops

See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=34114#c3 and
following for an explanation.

Of course gcc is completely wrong and stupid here, because there's no
possibility on current or future hardware that an array of size
SSIZE_MAX could be allocated since it would by definition occupy at
least all addressible memory (if it was an array of bytes, which this
isn't), leaving no room for the code that is being compiled.

daemon/debug.c

@@ -547,7 +547,7 @@ debug_progress (const char *subcmd, size_t argc, char *const *const argv)
     uint64_t tsecs = secs * 10; /* 1/10ths of seconds */
     uint64_t i;
 
-    for (i = 1; i <= tsecs; ++i) {
+    for (i = 1; i < tsecs+1; ++i) {
       usleep (100000);
       notify_progress (i, tsecs);
     }

daemon/lvm.c

@@ -215,7 +215,7 @@ do_vgcreate (const char *volgroup, char *const *physvols)
   argv[0] = str_lvm;
   argv[1] = "vgcreate";
   argv[2] = volgroup;
-  for (i = 3; i <= argc; ++i)
+  for (i = 3; i < argc+1; ++i)
     argv[i] = physvols[i-3];
 
   r = commandv (NULL, &err, (const char * const*) argv);
@@ -522,7 +522,7 @@ do_vg_activate (int activate, char *const *volgroups)
   argv[1] = "vgchange";
   argv[2] = "-a";
   argv[3] = activate ? "y" : "n";
-  for (i = 4; i <= argc; ++i)
+  for (i = 4; i < argc+1; ++i)
     argv[i] = volgroups[i-4];
 
   r = commandv (NULL, &err, (const char * const*) argv);

daemon/md.c

@@ -467,7 +467,7 @@ parse_md_stat_line (char *line)
   return ret;
 
  error:
-  for (i = 0; i <= spaces; ++i) {
+  for (i = 0; i < spaces+1; ++i) {
     free (ret->guestfs_int_mdstat_list_val[i].mdstat_device);
     free (ret->guestfs_int_mdstat_list_val[i].mdstat_flags);
   }

daemon/xattr.c

@@ -376,7 +376,7 @@ do_internal_lxattrlist (const char *path, char *const *names)
      * entry[1..nr_attrs] are the attributes.
      */
     entry = &ret->guestfs_int_xattr_list_val[ret->guestfs_int_xattr_list_len-nr_attrs-1];
-    for (m = 1; m <= nr_attrs; ++m) {
+    for (m = 1; m < nr_attrs+1; ++m) {
       entry[m].attrname = NULL;
       entry[m].attrval.attrval_len = 0;
       entry[m].attrval.attrval_val = NULL;

src/drives.c

@@ -524,7 +524,7 @@ add_drive_to_handle_at (guestfs_h *g, struct drive *d, size_t drv_index)
   if (drv_index >= g->nr_drives) {
     g->drives = safe_realloc (g, g->drives,
                               sizeof (struct drive *) * (drv_index + 1));
-    while (g->nr_drives <= drv_index) {
+    while (g->nr_drives < drv_index+1) {
       g->drives[g->nr_drives] = NULL;
       g->nr_drives++;
     }