optional_depends -sub CXX gcc                             \
                  '--enable-cxx'                  \
                  '--disable-cxx'                 \
                  'for C++ language recognition'  &&

optional_depends  JAVA                             \
                  '--enable-java'                  \
                  '--disable-java'                 \
                  'for Java language recognition'  &&

optional_depends  mono                           \
                  '--enable-csharp'              \
                  '--disable-csharp'             \
                  'for C# language recognition'  &&

optional_depends  python                             \
                  '--enable-python'                  \
                  '--disable-python'                 \
                  'for Python language recognition'

.