Re: [Qemu-devel] [PATCH] configure: preserve various environment variables in config.status

[Stefan Weil <sw@weilnetz.de>]

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Am 17.11.2015 um 18:59 schrieb Daniel P. Berrange:
> Suggested in
>
>   https://lists.gnu.org/archive/html/qemu-devel/2015-11/msg03298.html
>
> The config.status script is auto-generated by configure upon
> completion. The intention is that config.status can be later
> invoked by the developer to re-detect the same environment
> that configure originally used. The current config.status
> script, however, only contains a record of the command line
> arguments to configure. Various environment variables have
> an effect on what configure will find. In particular the
> PKG_CONFIG_LIBDIR & PKG_CONFIG_PATH vars will affect what
> libraries pkg-config finds. The PATH var will affect what
> toolchain binaries and XXXX-config scripts are found. The
> LD_LIBRARY_PATH var will affect what libraries are found.
> All these key env variables should be recorded in the
> config.status script.
>
> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> ---
>
> Open question: are there more env vars we should preserve ?

Probably yes. They can be added as soon as we discover them.

>
>  configure | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
>
> diff --git a/configure b/configure
> index d7472d7..9c9f6ac 100755
> --- a/configure
> +++ b/configure
> @@ -5925,6 +5925,24 @@ cat <<EOD >config.status
>  # Compiler output produced by configure, useful for debugging
>  # configure, is in config.log if it exists.
>  EOD
> +
> +preserve_env() {
> +    envname=$1
> +
> +    if test -n "${!envname}"
> +    then
> +    echo "$envname=\"${!envname}\"" >> config.status
> +    echo "export $envname" >> config.status

else
    echo "unset $envname" >>config.status

>
> +    fi
> +}
> +
> +# Preserve various env variables that influence what
> +# features/build target configure will detect
> +preserve_env PATH
> +preserve_env LD_LIBRARY_PATH
> +preserve_env PKG_CONFIG_LIBDIR
> +preserve_env PKG_CONFIG_PATH
> +
>  printf "exec" >>config.status
>  printf " '%s'" "$0" "$@" >>config.status
>  echo >>config.status

With the additional code for unset variables this
patch is nearly perfect. Even without it, it is a
reasonable improvement.

Reviewed-by: Stefan Weil <sw@weilnetz.de>

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