Re: Building old systems

[Havard Eidnes <he%NetBSD.org@localhost>]

>> Indeed, this (without -O) works.  The key is the HOST_CFLAGS
>> variable; I was thinking of just CFLAGS at first.
> 
> I have had some luck with compiling old systems with -V
> HOST_CFLAGS=-fcommon.
> 
> That only goes so far into the past, however.  I thought the
> next step would be to try building even older systems with the
> compiler from oldest successful build.  So, I tried setting
> HOST_CC and HOST_CXX to point to an oldish, but successfully
> built toolset that also successfully compiled its own kernel.
> That is, I run build.sh with -V
> HOST_CC=/path/to/oldish/tooldir/bin/armv7--netbsdelf-eabihf-gcc
> (and similarly for HOST_CXX), where those compilers are not the
> native systems compilers but ones used in a successful kernel
> build for a checkout somewhat after the target checkout.
>
> That has led to errors like the following:
>
> 	/path/to/oldish/tooldir/bin/ld: cannot find crt0.o: No such file or directory
>
> I'm guessing this means that some other environment variables
> are not set so the compiler is looking in the wrong place, but
> BUILDING is not helping me think of what that would be.  All
> paths are absolute, except they do include ".." In them.
>
> What should I be configuring to make sure that a tooldir
> compiler is usable?

What I think I would do would be to use HOST_CFLAGS=-fcommon to
do a "./build.sh ... tools" build.  This should, at least in
theory, result in a self-consistent and hopefully working
toolchain of the same vintage as the kernel you are trying to
build.  Try this especially if it's somewhat uncertain where the
/path/to/oldish/tooldir was built from.

Best regards,

- Håvard