Re: Cross compile gpsd-3.20.1~dev for arm with buildroot

[Greg Troxel]

sysconfig is about the host.   It is broken to use host path information when 
building cross.   Cross paths need explicit config on the build command line, 
tests in the sysroot or similar.

When you have a destdir with a cross os/arch, and you are using pkg-config, you 
look for .pc files in the destdir and you ignore the host filesystem.  AIUI you 
can't do that with python.  That's a python bug but it is longstanding.

The notion that the build system is not aware of cross vs not is therefore also 
more or less broken.  Probably there should be a cross option,  and if true, 
lots of things set explicitly as options, and if false looked for on the host.  
Some things can be looked for in the sysroot.

Part of the trouble is likely conflating sysroot (cross place with headers and 
libs) and destdir (extra prefix for installing).  But I have not dug in to how 
the scons build works any more than I have to.

The thing that you are missing is believing that the current build does cross 
almost right and just needs a tweak.  It needs someone who really understands 
cross building to dig in.  The autoconf build system in the end got this 
exactly right -- autoconf was designed for cross, and I fixed up the issues 
because I needed to build gpsd cross for $DAYJOB.  Now I don't and esr 
converted to scons which claims to do cross but seems to require a project to 
write code to do that.

None of the gpsd maintainers actively care about cross right now.  People that 
do build cross tend to turn off python and anything else they can.  Hence we 
are still in a cross-not-really-ok situation, many years later.

All that said, someone fixing this isn't that hard, if they really understand 
and actually make it  sound.  I  am not suggesting gpsd change back to 
autoconf, but study the autoconf cross docs.

Gary: please don't merge cross patches without me having a chance to review.