Ancient msgfmt doesn't know about generics.
This change allows devs to set javac.compilerargs=-Xlint:unchecked
in override.properties without getting an
overwhelming number of false positives from the bundles.
If msgfmt ever adds a --java5 option, we can remove this,
but it's been almost 20 years.
For the same reason, while the sed script is fragile,
seems unlikely msgfmt will change the output without a new option.
If they do, we'll fix it then.
This solves the following problem which was found on OpenBSD:
bundle:
[exec] Generating net.i2p.desktopgui.messages_ar ResourceBundle...
[exec] ERROR - msgfmt failed on locale/messages_ar.po, not updating translations
[exec] msgfmt: Java compiler not found, try installing gcj or set $JAVAC
[exec] msgfmt: compilation of Java class failed, please try --verbose or set $JAVAC
[exec] 9 translated messages.
In OpenBSD 5.4, neither java nor javac are in the PATH.
zzz