No longer automatically append the `--export` flag for each exported
function unconditionally. This was essentially a hack to prevent
binary bloat caused by compiler-rt symbols being always included in
the final binary as they were exported and therefore not garbage-
collected. This is no longer needed as we now support the ability to
set the visibility of exports.
This essentially reverts 6d951aff7e32b1b0252d341e66517a9a9ee98a2d