in a file named

BUILD.tools

in the root of the repo:

jar_library(name = 'antlr-4',
            jars = [
              jar(org = 'org.antlr', name = 'antlr4', rev = '4.4'),
              jar(org = 'org.antlr', name = 'antlr4-runtime', rev = '4.4'),
            ])