usage: ./build.sh [-c] [-nd] [-r ALL|name[:step]] [-h] [-t]
         -c                     Clean $PREFIX before processing build scripts.
         -nd                    Don't rm(1) and re-download tarballs when not required.
         -r ALL|name[:step]     Restart all or the specified build script(s) completely
                                or at the optionally specified build step. Currently defined
                                build steps are: fetch extract patch configure clean build
                                install configure1 configure2 build1 build2 install1 install2
                                install3.
         -h                     Show this screen.
         -t                     Produce a distribution tarball containing $PREFIX
                                sans $WORKDIR and $PREFIX/src/midipix_build at the end of a
                                build with zero failures.

        Packages that are built by pkg.build will apply local patches in $WORKDIR
        named ${PKG_SUBDIR}.local.patch.

        Examples:
        ./build.sh -r psxscl GITROOT_HEAD=... PKG_PSXSCL_CFLAGS=-DPSX_INTERNAL_STRACE
        Build psxscl from the internal repository with strace enabled.

        ./build.sh -c -r ALL GITROOT_HEAD=...
        Clean $PREFIX and forcibly rebuild everything.