Upgrading toolchain gcc to 7.2

Hi everyone,

For a past month I'm trying to help the minix project with upgrading the gcc version that they are using. This is due to the fact that the core developers believe that a bug in gcc is causing binary misalignement on Beagle Bone Black. My idea was to update the gcc in hope the newer versions would be free of that problem.

NetBSD currently uses gcc 5.3 and minix is still on 4.8, but I personally wanted to go to the latest 7.2.

Now the problem I have is that I don't really know how the netbsd build process looks like and whilst the gcc as a tool compiled without any problems when building on the target platform evbearm it fails.

Thus my questions to You are:

1) What steps have You taken when upgrading the gcc? Did You have to update binutils as well or some other tools?

2) What functional changes have You made to the gcc itself? I've looked at the diff extensively but apart from adding new platforms and removing testsuites I can't understand the reasons behind other changes that have been made. A guiding hand would be helpful.

3) A more general question about the build system. I understand that /tools/gcc has the makefiles for building the cross-compilation toolchain. But what is the purpose of /external/gpl3/gcc/lib and usr.bin. Why do they have to be separate from the ../dist? And how have You came up what files to include in those tools?

Cheers,

Radek