Re: Cross-compiling git (was: [PATCHv2] add Android support)

[Jeff King <peff@peff.net>]

On Mon, May 23, 2011 at 12:04:44AM -0700, Jakub Narebski wrote:

> > So I think we are probably stuck either with the user setting an ANDROID
> > meta-flag that sets the other flags appropriately, or leaving it up to
> > the user to provide a sane config.mak.
> 
> By the way, how well Git supports cross-compiling (which from the
> thread is necessity to generate binaries for Android)?  `uname -a`
> trick works only when compiling on same machine.

It should work fine if you set the make variables appropriately for the
target platform. But I've never tried it. Didn't msysgit people
cross-compile for a while (or maybe still do)?

> ./configure supports --host and --build options, but I don't know if
> it pass them down to make somehow.  ANDROID=YesPlease seems wasteful:
> what about setting HOST or MACHINE, or even uname_* variables, or just
> using Autoconf's `host` (in the form of CPU-VENDOR-OS)?

I know very little about autoconf internals, but what would
CPU-VENDOR-OS look like? Your CPU is probably some arm variant, though
it will vary from device to device. Your kernel is Linux. The special
steps in this case are about some weird userspace issues. So the
equivalent would be more like finding a Linux distro that ships a crappy
libc.  I guess that is what the "vendor" slot is for?

But even if you somehow tell autoconf or the Makefile "yes, this is
android", you are still going to need to manually specify the set of
knobs that should be tweaked in that case. Whether you call it
"ANDROID=YesPlease" or some other form.

-Peff