sdcc: add reminder to remove .PHONY patch with next release

  # filesystem), the INSTALL file keeps the `install` target in the ucsim

  # directory from running. Nothing else creates the `man` output, causing the

  # entire build to fail.

  #

  # TODO: remove this when updating to the next release - it's been fixed in

  # upstream sdcc r15384 <https://sourceforge.net/p/sdcc/code/15384/>.

  postPatch = ''

    if grep -q '\.PHONY:.*install' sim/ucsim/Makefile.in; then

      echo 'Upstream has added `.PHONY: install` rule; must remove `postPatch` from the Nix file.' >&2

      exit 1

    fi

    echo '.PHONY: install' >> sim/ucsim/Makefile.in

  '';