{pre_hooks, [
    {"(linux|darwin|solaris)", compile, "make -C c_src"},
    {"(freebsd|openbsd|netbsd)", compile, "gmake -C c_src"}
    ]}.

{post_hooks, [
    {"(linux|darwin|solaris)", clean, "make -C c_src clean"},
    {"(freebsd|openbsd|netbsd)", clean, "gmake -C c_src clean"}
    ]}.