5pkgs.elinks: meson build to fix gettext 0.23.1 break
nixpkgs's autotools elinks 0.19.1 fails against gettext 0.23.1
(autopoint refuses bare AM_GNU_GETTEXT, then autoheader fails on
HAVE_ALLOCA). Carry the meson-based build from upstream nixpkgs
PR #515347 locally until it lands; tools.mutt now consumes
self.packages.<system>.elinks instead of pkgs.elinks.
Inlines the libcss/libdom propagatedBuildInputs adjustments from the
same PR, scoped to this elinks build only — no global overlay.