Re: [Qemu-devel] [PATCH] Fix cross compilation

[Aurelien Jarno <aurelien@aurel32.net>]

On Sun, Mar 28, 2010 at 11:44:05AM +0200, Stefan Weil wrote:
> This patch enhances the algorithm which finds the correct settings for SDL.
> For cross compilations (when cross_prefix is set), it looks for sdl-config
> with cross prefix. Here is the complete search order:
> 
> ${cross_prefix}sdl_config              (new, only used for cross compilation)
> $(cross_prefix}pkg-config              (old)
> pkg-config                             (old, needs PATH)
> sdl-config                             (old, needs PATH)

Why a different order for cross-compilation than for native
compilation? I would expect the same order in both case, that is
pkg-config first, and then sdl_config. The general rule, not specific to
QEMU, is to prefer pkg-config over *config programs.

> Cross SDL packages (or the user) now can simply set a link (for example
> /usr/bin/i586-mingw32msvc-sdl-config -> /usr/i586-mingw32msvc/bin/sdl-config)
> which allows cross compilations without PATH modifications.
> 
> Without the patch, configure and make (which calls configure) typically
> need a non-standard PATH. Failing to set this special PATH results in
> broken builds.
> 
> Signed-off-by: Stefan Weil <weil@mail.berlios.de>
> ---
>  configure |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)
> 
> diff --git a/configure b/configure
> index 664c920..eb2d759 100755
> --- a/configure
> +++ b/configure
> @@ -1047,7 +1047,10 @@ fi
>  ##########################################
>  # SDL probe
>  
> -if $pkgconfig sdl --modversion >/dev/null 2>&1; then
> +if test -n "$cross_prefix" && has ${cross_prefix}sdl-config; then
> +  sdlconfig="${cross_prefix}sdl-config"
> +  _sdlversion=`$sdlconfig --version | sed 's/[^0-9]//g'`
> +elif $pkgconfig sdl --modversion >/dev/null 2>&1; then
>    sdlconfig="$pkgconfig sdl"
>    _sdlversion=`$sdlconfig --modversion 2>/dev/null | sed 's/[^0-9]//g'`
>  elif has sdl-config; then
> -- 
> 1.7.0
> 
> 
> 
> 

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net