Re: [Qemu-devel] [PATCH] Fix SDL configuration for mingw32 cross compilation.

[Jamie Lokier <jamie@shareable.org>]

Stefan Weil wrote:
> Jamie Lokier schrieb:
> > Anthony Liguori wrote:
> >   
> >> Stefan Weil wrote:
> >>     
> >>> Anthony Liguori schrieb:
> >>>  
> >>>       
> >>>> Stefan Weil wrote:
> >>>>    
> >>>>         
> >>>>> When building QEMU for win32 on linux with mingw32,
> >>>>> configure must call ${cross_prefix}-sdl-config (not
> >>>>> sdl-config) to get the correct include and lib paths.
> >>>>>
> >>>>> The results of the native sdl-config are only valid
> >>>>> for native builds. They are useless for cross builds.
> >>>>>  
> >>>>>      
> >>>>>           
> >>>> No, when you cross compile sdl, you still end up with an sdl-config
> >>>> binary.  The solution is to install the binary to a different path and
> >>>> use PATH when building.
> >>>>
> >>>> Where did you get your cross build of SDL from?  I assume whoever
> >>>> packaged it renamed the binary but it's not what sdl actually does.
> >>>>
> >>>>    
> >>>>         
> >>> The PATH solution works (I used it, too), but it is bad:
> >>> you have to use a modified PATH for every cross build
> >>> (make calls configure when the configure script is updated).
> >>>  
> >>>       
> >> Yes, this annoys me too.  One thing I thought about is that we could 
> >> record important environment variables for use when re-running make.
> >> It's not just PATH.  PKG_CONFIG_PATH is also important for running 
> >> configure.  To properly cross compile, you need to set both.
> >>     
> >
> > You can record PATH and other environment variables picked up at
> > configure time in the Makefile itself.  Makefile.in:
> >
> >    export PATH = @PATH@
> >
> > It's not pretty, but it works.
> >
> > -- Jamie
> >
> >   
> 
> Only with autoconf / automake? QEMU does not use them,
> so there is no Makefile.in.
> 
> I'd prefer setting paths for pkg-config and sdl-config via
> configure options (those are recorded in config-host.mak).

You can use it with anything which controls the variables like $(CC)
in Makefiles.  Doesn't have to be Autoconf.

So you'd either put PATH=... and PKG_CONFIG_PATH=... in
config-host.mak plus "export PATH PKG_CONFIG_PATH" in the Makefile, or
you'd put "export PATH=..." and "export PKG_CONFIG_PATH=..." in
config-host.mak and nothing in the Makefile.

The main thing is, after recording them, you might have to export PATH
in Makefile or config-host.mak to have the required effect.  I guess
PKG_CONFIG_PATH won't need exporting globally; only in commands which
call pkg-config.

-- Jamie