Bug#893102: brltty FTBFS with openjdk-9

[Adrian Bunk]

Source: brltty
Version: 5.6-2
Severity: serious

https://tests.reproducible-builds.org/debian/rb-pkg/unstable/amd64/brltty.html

...
'/usr/lib/jvm/java-9-openjdk-amd64/bin/javac' -encoding UTF-8 -source 1.5 -target 1.5 -d classes -classpath . ../../../Bindings/Java/Brlapi.java ../../../Bindings/Java/ConnectionSettings.java ../../../Bindings/Java/DisplaySize.java ../../../Bindings/Java/Error.java ../../../Bindings/Java/Exception.java ../../../Bindings/Java/Key.java ../../../Bindings/Java/Native.java ../../../Bindings/Java/Test.java ../../../Bindings/Java/WriteArguments.java Constants.java
warning: [options] bootstrap class path not set in conjunction with -source 1.5
error: Source option 1.5 is no longer supported. Use 1.6 or later.
error: Target option 1.5 is no longer supported. Use 1.6 or later.
make[3]: *** [Makefile:96: classes.made] Error 2