I suggest looking at LinuxFromScratch[0], especially II.5. It's hard to do a "real" cross-platform compiler because your target system might not only be a different architecture but also has different libraries on the system with which the compiler has to work. All in all, doing it right and being able to ship binaries is a lot of work and constant maintenance as your target system, in this case Raspbian, also changes their libraries.
Re:Quake III bounty: we have a winner
by raverbashing on Monday March 31, 2014 @10:15AM
(#7501558)
Some issues:
Your GCC build has to match the userspace C library (uclibc or other). If it doesn't you'll need to do all the path passing and usually link manually as well.
It has also to match the kernel somewhat (not so critical for userspace apps, but if you want to add a module or something it's critical)
So, basically what you "should do" is build the whole system together (cross-compiler + userspace + kernel), some tools do that, building first a "raw" cross-compiler, then the C library and kernel, then a full compiler with all the options applied.
Here is a great explanation of why setting up a cross compiler is so difficult.
Couldn't somebody build a full cross-compiler toolchain as "relocatable" binaries, depending on an older kernel, and then just offer that as a binary download to run on most recent distributions? It's not a typical way to distribute a linux application, but it should work in principle.