this is an interesting exercise; however, it is much harder than it needs
to be. perhaps you have other reasons for doing it the hard way.

i posit that bringing up plan9 on qemu and compiling /sys/src is faster
than compiling on macos: kencc+p9p+cross compile plan9 and bring up plan9
on qemu.  i would be happy to be proven wrong.



On Mon, Jul 7, 2014 at 10:41 AM, Yoann Padioleau <pad@fb.com> wrote:

>  Hi,
>
>  I was able to cross compile Plan9 from MacOS which is probably quite
> similar
> to cross compiling from Linux.
>
>  The first thing was to compile the plan9 C compilers
> on MacOS. I used https://code.google.com/p/ken-cc/ because this fork
> of the Plan9 C compilers are easier to compile on non-plan9 OSes.
>
>  Then I installed plan9port which contained a few utilities that are used
> when compiling the plan9 kernel (/bin/rc, /bin/mk).
>
>  Then I setup a few symlinks at the root e.g.
>
>  /lib -> /home/pad/plan9/root/lib
> /386 -> /home/pad/plan9/root/386
> /sys -> /home/pad/plan9/sys
>
>  Finally I have a env.sh that I source that contains important
> environment variables:
>  export KENCC=/home/pad/kencc
> # need to modify plan9/src/cmd/mk/shell.c and put rcshell as default shell
> export PLAN9=/usr/local/plan9
>
>  export PATH=$PLAN9/bin:$KENCC/bin:$PATH
>
>  #for 8._cp to be found and called
> PATH=$PATH:.
>
>  export objtype=386
> #export objtype=arm
> export cputype=386
>
>  Then I did a few modifications to plan9 Labs and was able to compile and
> run everything
> under qemu.
>
>  My forks:
> https://github.com/aryx/fork-kencc
> https://github.com/aryx/fork-plan9
>
>
>  On Jul 5, 2014, at 7:02 AM, Charles Forsyth <charles.forsyth@gmail.com>
>  wrote:
>
>
> On 5 July 2014 14:13, Aleksandar Kuktin <akuktin@gmail.com> wrote:
>
>>
>> Are there any pointers or short instructions or a HOWTO or something
>> similar on the art of cross-compiling Plan 9 from Linux?
>>
>
> It would be easier to compile using 9vx under Linux, or a virtual plan 9
> machine in qemu under Linux.
> It is possible to cross-compile directly, but I've only built and used
> that environment twice myself
> (once for Solaris, once for Linux), and it isn't any longer in any
> distributable shape. It might reappear
> as a side effect of some work on the compiler suite. It's similar to the
> way Inferno's kernel is cross
> compiled using the Plan 9 compilers hosted by some other OS, but needs a
> few special twists to
> deal with the Plan 9 source tree.
>
>
>