PR fortran/40958
* scanner.h: New file.
* Make-lang.in: Dependencies on scanner.h.
* scanner.c (gfc_directorylist): Move to scanner.h.
* module.c: Don't include md5.h, include scanner.h and zlib.h.
(MOD_VERSION): Add comment about backwards compatibility.
(module_fp): Change type to gzFile.
(ctx): Remove.
(gzopen_included_file_1): New function.
(gzopen_included_file): New function.
(gzopen_intrinsic_module): New function.
(write_char): Use gzputc.
(read_crc32_from_module_file): New function.
(read_md5_from_module_file): Remove.
(gfc_dump_module): Use gz* functions instead of stdio, check gzip
crc32 instead of md5.
(read_module_to_tmpbuf): Use gz* functions instead of stdio.
(gfc_use_module): Use gz* functions.