app-i18n/enca: verbump to 1.19

app-i18n/enca: verbump to 1.19

Major ebuild overhaul:
- EAPI=6, migrate away from deprecated eclasses;
- fix 404 HOMEPAGE;
- do not enable recode by default as its upstream is dead;
- introduce iconv USE to avoid iconv automagic dependency;
- introduce static-libs USE;
- add missing gtk-doc dep for doc USE;
- make build system respect doc USE;
- avoid ugly cross compilation and multilib hacks by doing things right.

Gentoo-Bug: https://bugs.gentoo.org/593220
Closes: https://github.com/gentoo/gentoo/pull/2340

Package-Manager: portage-2.3.0

Signed-off-by: Yixun Lan <dlan@gentoo.org>