Depending on whether thumb or arm is used, the snippet of inline asm
won't work (as some of it is decided in a later pass than the
preprocessor).

moving it from pimp_mixer_arm.S, so that all config options are in one
place

if IRQ_SAFE is defined, this variable is never used, so this saves a
tiny bit of memory.

Travis cleanups

A long time ago, setting sudo to false was the way to get builds
run in the faster container-based infrastructure. That's no longer
the case, and we actually use sudo. So let's drop that line.

The new pacman-based devkitPro installer is so fast that there's
really no point in caching here, it takes more time to download the
cache than to reinstall.

Pacman

This is where gbafix and the gbfs tools reside these days, it seems.

Due to one of the original author's name, we need special characters
in the copyright-statement. This was originally done with ISO-8859-1,
but in these days UTF-8 is the defactor standard.

So let's re-encode all text-files to UTF-8.

We don't always have C99-support, so let's declare the loop-counter
at the top of the functions.

While we're at it, port load_xm.c and load_mod.c, as well as the
tests.

This should fix the 64-issue on non-Windows platforms.

This pointer relocation doesn't work on 64-bit architectures, and
needlessly depends on C++. Let's rewrite it a bit to avoid both of
these details.

devkitARM has changed their prefix, so let's play catch-up.