patch [#34103]

from Lawrence D'Oliveiro (ldo)

More use of bool type, necessitating adding inclusion of BLI_utildefines.h, or moving it up in the inclusion order if it was already included, in various places
- storage.c: make some variables only used in bli_builddir local to that
- storage.c: BLI_file_descriptor_size should allow 0 as a valid file descriptor
- path_util.c: make pointers to non-reentrant storage returned from folder routines const, necessitating making variables holding these returned pointers const elsewhere as well
- path_util.c: BLI_string_to_utf8 closes iconv context in case of conversion error
-  blf_lang.c: fill_locales routine now has its own "languages" local variable to construct paths (was stealing internal storage belonging to BLI_get_folder before)

source/blender/blenkernel/intern/tracking.c

@@ -1773,6 +1773,7 @@ ImBuf *BKE_tracking_sample_pattern(int frame_width, int frame_height, ImBuf *sea
 	(void) frame_height;
 	(void) search_ibuf;
 	(void) marker;
+	(void) from_anchor;
 	(void) track;
 	(void) use_mask;