Fix Stage1Only: don't build ghctags.

ghctags needs the stage2 compiler, since it uses the GHC API.

Fixes #8126.

Authored-by: Stephen Blackheath <...@blacksapphire.com>
Signed-off-by: Austin Seipp <aseipp@pobox.com>
iOS: generate archive files when compiling.

When cross compiling to iOS, we generate archive files which are linked
into the final executable. We already *did* generate archive files -
just with the wrong suffix.

Fixes #8125.

Authored-by: Stephen Blackheath <...@blacksapphire.com>
Signed-off-by: Austin Seipp <aseipp@pobox.com>
Bump supported llvm version to 3.4.

The compiler can bootstrap and run all tests fine, given a copy of LLVM
built on Jul 27 2013.

Signed-off-by: Austin Seipp <aseipp@pobox.com>
Don't run the system linker unncessarily.

This wastes time when evaluating expressions in GHCi. We also
disable object unloading when using the dynamic linker, too.

Fixes #7382. Fixes #7326.

Signed-off-by: Austin Seipp <aseipp@pobox.com>