 macro.  Later definitions/redefinitions/ undefinitions take
        precedence.

        'include_dirs', if given, must be a list of strings, the
        directories to add to the default include file search path for this
        compilation only.

        'debug' is a boolean; if true, the compiler will be instructed to
        output debug symbols in (or alongside) the object file(s).

        'extra_preargs' and 'extra_postargs' are implementation- dependent.
        On platforms that have the notion of a command-line (e.g. Unix,
        DOS/Windows), they are most likely lists of strings: extra
        command-line arguments to prepend/append to the compiler command
        line.  On other platforms, consult the implementation class
        documentation.  In any event, they are intended as an escape hatch
        for those occasions when the abstract compiler framework doesn't
        cut the mustard.

        'depends', if given, is a list of filenames that all targets
        depend on.  If a source file is older than any file in
        depends, then the source file will be recompiled.  This
        supports dependency tracking, but only at a coarse
        granularity.

        Raises CompileError on failure.
        )