[B]ack port of part of r565301 | gerald | 2021-02-15 from
lang/gcc11-devel:

  Explicitly build --without-zstd such that archivers/zstd isn't pulled
  in inadvertedly when present in the build system even though it is not
  an explicit dependency. [1]

Remove the GRAPHITE option. Graphite still is a largely experimental
feature, so better left to newer versions of GCC such as GCC 10 which
is now our default.