Add support for recent Java versions.
Reported by Emmanuel Bourg <ebourg@apache.org>
at <https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=892733>
via Santiago Vila.
* gettext-runtime/configure.ac: Require a Java compiler that supports
source-version 1.5 and target-version 1.6 (such as Java 6 or newer, or
GCJ 4.3 or newer).
* gettext-tools/src/write-java.c (msgdomain_write_java): Likewise
* gettext-tools/examples/hello-java-qtjambi/configure.ac: Likewise.
* gettext-tools/configure.ac: Require a Java compiler that supports
source-version 1.5 (such as Java 5 or newer, or GCJ 4.3 or newer).
* gettext-tools/examples/hello-java/configure.ac: Likewise.
* gettext-tools/examples/hello-java-awt/configure.ac: Likewise.
* gettext-tools/examples/hello-java-swing/configure.ac: Likewise.
* NEWS: Mention the change.
