Update to upstream version 1.3.4 [1], take maintainership [2]

While on it:

• Handle CFLAGS with xvid's build system [2]
• Remove superfluous ln -sf in post-patch (now handled by xvid's build system) [2]
• Pet portlint [2]

PR: 203626
Submitted by: w.litter@aon.at [1]
Reviewed by: riggs [2]