CompilerArgs: make lookup faster
CompilerArgs: make lookup faster

in order to deduplicate arguments as much as possible, we need to check
if a argument is already part of the list. Which is quite slow because
we are checking 3 lists for that.

In smaller projects this might be not of interested. However, in efl
things are quite "heavy", alone generating the ninja file took 40 sec..
16 sec. are spent in __iadd__ of CompilerArgs.

What this patch does to speed this all up is:
1. We only check if a element is in post when we know that it must be in
   post same for pre.
2. the checks for if we already do contain a specific value are now done
   via a dict, and not via the list.

This overall brings the time from 16 sec. spent in __iadd__ to 9 sec. in
__iadd__.

Another possible solution for all this is to have a internal structure
of CompileArgs of trees, so you have the "basic" layer of arguments
where the position does not matter. Additionally, you have two stacks of
lists, the pre stack and the post stack, duplicates can then be checked
when itereting, which would safe another ~4s in terms of efl. However, i
do not have time for this undertaking right now.

mesonbuild/meson,mesonbuild/meson,QuLogic/meson,mesonbuild/meson,mesonbuild/meson,QuLogic/meson,becm/meson,QuLogic/meson,QuLogic/meson,QuLogic/meson,pexip/meson,jpakkane/meson,QuLogic/meson,jpakkane/meson,jpakkane/meson,mesonbuild/meson,jpakkane/meson,QuLogic/meson,becm/meson,pexip/meson,pexip/meson,pexip/meson,becm/meson,jpakkane/meson,pexip/meson,mesonbuild/meson,pexip/meson,mesonbuild/meson,pexip/meson,pexip/meson,becm/meson,pexip/meson,becm/meson,QuLogic/meson,becm/meson,mesonbuild/meson,jpakkane/meson,jpakkane/meson,mesonbuild/meson,becm/meson,mesonbuild/meson,QuLogic/meson,becm/meson,jpakkane/meson,jpakkane/meson,pexip/meson,becm/meson,becm/meson