Bug#523051: antlr-config --cxxflags doesn't work

[Max Kellermann]

Package: libantlr-dev
Version: 2.7.7-10

The --cxxflags option is advertised in the usage text, but isn't
actually understood:

max at rabbit:~$ antlr-config --cxxflags
Usage: antlr-config [OPTIONS] [LIBRARIES]
Options:
        [--prefix[=DIR]]
        [--exec-prefix[=DIR]]
        [--version]
        [--libs]
        [--cflags]
        [--cxxflags]
Libraries:
        libantlr.a
max at rabbit:~$ echo $?
1