* gnu/build/file-systems.scm (%fat32-endianness, fat32-superblock?, read-fat32-superblock, fat32-superblock-uuid, fat32-uuid->string, fat32-superblock-volume-name, check-fat32-file-system): New variables. (%partition-label-readers, %partition-uuid-readers, check-file-system): Add fat support. (latin1->string): New variable. (null-terminated-latin1->string): Use latin1->string.