Re: Cross compiling a program

AGC<agcarver+netbsd%acarver.net@localhost>  writes:

Is there a helpful document somewhere that describes the process of
cross compiling a program for use under NetBSD/sparc?

I'm not sure.

I want to compile newer versions of gpsd but the project maintainers
have switched away from configure scripts to python and SCons, neither
of which will compile and install for NetBSD/sparc.  I do have,
however, several Debian/x86 systems that have working versions of both
of those programs.  I want to be able to compile gpsd on one of those
Debian systems but generate a NetBSD/sparc binary.

You only need scons on the build system.

I am surprised that python will not build on NetBSD/sparc.  I am pretty
sure I had a test environment for gpsd (pre-scons, post-python) on an
IPX running NetBSD 4.0_STABLE.

Most of the documentation discusses cross compiling NetBSD itself
(which I may do later if I can't figure out how to upgrade NetBSD in
place, but that's a totally different effort that I'm having trouble
following).

For upgrading, see pkgsrc/sysutils/etcmanage and read very carefully
BUILD-NetBSD and INSTALL-NetBSD.  That encapsulates how I deal with
upgrading.  Note also that boot blocks have compatibility issues, so
that if you update a sparc in place from 1.6 to 6.0 then I think boot
blocks that are 2.0 or newer don't boot 4.0 kernels, but I am fuzzy on
the details.  I think each single-version jump is ok in that the
up-to-date X boot blocks can boot X+1.

I don't see anything about individual programs that are
downloaded from source.

To cross-compile from source, do

   full build.sh of NetBSD/sparc, matching version what you are going to
   run.  (I use BUILD-NetBSD, but it just picks defaults that I like,
   mostly.)

   use the cross-compiler toolchain from above, either writing wrapper
   scripts or using the right PATH, or autoconf support.  Note that you
   almost certainly want to use --sysroot to point to the DESTDIR so you
   get the right include files.  You may need to make a directory
    I containing cpp, cc, and so on that basically does
     cc --sysroot=/your/destdir $*
   and use that directory as your compiler path.

   [those two steps are not all that hard]

   Make the program you want to build cross-build safe.  Things with gnu
   autoconf are generally pretty close, SCons not so much.
   Cross-building is one of the things gpsd decided not to care about
   when they moved to scons.   I think that was a bad technical decision;
   everyone rants about how autoconf is complicated, but almost always I
   see people propose replacing it with setups that lack out-of-srcdir
   builds, cross builds, support for making  a distfile and running a
   non-srcdir build and make check, etc.

I have never tried to cross-compile python; I am not particularly
optimistic.