multimedia/ogmtools: Improve port

* Define LICENSE
* Clean up Makefile
* Import patches from Debian and Gentoo for various bug fixes

References:
https://sources.debian.org/src/ogmtools/1%3A1.5-4.1/debian/patches/0001-configure.in-adjust-variable-formatting.patch/
https://sources.debian.org/src/ogmtools/1%3A1.5-4.1/debian/patches/0002-ogmsplit.1-spell-correct.patch/
https://sources.debian.org/src/ogmtools/1%3A1.5-4.1/debian/patches/0003-ogmmerge-spell-correct.patch/
https://sources.debian.org/src/ogmtools/1%3A1.5-4.1/debian/patches/0004-ogminfo-timestamp-correction.patch/
https://sources.debian.org/src/ogmtools/1%3A1.5-4.1/debian/patches/0006-pass-CFLAGS.patch/
https://gitweb.gentoo.org/repo/gentoo.git/tree/media-sound/ogmtools/files/ogmtools-1.5-comments.patch
https://gitweb.gentoo.org/repo/gentoo.git/tree/media-sound/ogmtools/files/ogmtools-1.5-endian-fix.patch
https://gitweb.gentoo.org/repo/gentoo.git/tree/media-sound/ogmtools/files/ogmtools-1.5-gcc11.patch