When libstdc++ was added in 4977fd22b8, just calling
'make install' was the easiest way to install the headers. And the headers are all
that is needed for libstdc++ to determine the ABI. Since then, BuildIt.sh was
rewritten again and again, and somehow everyone just silently assumed that
libstdc++ also depends on libc.a and libm.a, because surely it does?
Turns out, it doesn't! This massively reduces the dependencies of libstdc++,
hopefully meaning that the Toolchain doesn't need to be rebuilt so often on Travis.
Furthermore, the old method of trying to determine the dependency tree with
bash/grep/etc. has finally broken anyways:
https://travis-ci.com/github/SerenityOS/serenity/builds/179805569#L567
In summary, this should eliminate most of the Toolchain rebuilds on Travis,
and therefore make Travis build blazingly fast! :^)
We can do away with that shenanigans now that libstdc++ is gone.
Also, simplify the toolchain dependency hash calculation to only depend
on the toolchain build script(s) and the Patches files we use to modify
the toolchain itself.
It didn't feel right to have a "DHCPClient" in a "Servers" directory.
Rename this to Services to better reflect the type of programs we'll
be putting in there.
This should give a significant boost to Travis speeds, because most of the
compile time is spent building the toolchain over and over again.
However, the toolchain (or libc or libm) changes only rarely,
so most rebuilds can skip this step.
The hashing has been put into a separate file to keep it
as decoupled as possible from BuiltIt.sh.
