m4: Update to 1.4.19

m4: Update to 1.4.19

- Update from 1.4.18 (2016-12-31) to 1.4.19 (2021-05-28)
- patch no longer required as changes have been built into the source tarball.
- Update of rootfile
- Changelog is too large to fit here. Detail can be found in ChangeLog file in the
   source tarball.
   6 bugs fixed in this update.
	https://lists.gnu.org/archive/html/bug-m4/2021-04/msg00000.html
	https://lists.gnu.org/archive/html/bug-m4/2021-05/msg00001.html
	https://lists.gnu.org/archive/html/bug-m4/2020-03/msg00000.html
	https://lists.gnu.org/archive/html/bug-m4/2021-05/msg00002.html
	https://lists.gnu.org/archive/html/bug-m4/2021-05/msg00003.html
	https://lists.gnu.org/archive/html/bug-m4/2021-05/msg00004.html

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>