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Date: Fri, 24 Jul 2015 18:35:30 +0100
From: "Daniel P. Berrange" <berrange@redhat.com>
Message-ID: <20150724173530.GZ6880@redhat.com>
References: <1437758888-22486-1-git-send-email-peter.maydell@linaro.org>
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In-Reply-To: <1437758888-22486-1-git-send-email-peter.maydell@linaro.org>
Subject: Re: [Qemu-devel] [PATCH] configure: Work around broken static
 pkg-config info for Ubuntu gnutls
Reply-To: "Daniel P. Berrange" <berrange@redhat.com>
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>, qemu-devel@nongnu.org, patches@linaro.org

On Fri, Jul 24, 2015 at 06:28:08PM +0100, Peter Maydell wrote:
> Unfortunately Ubuntu's pkg-config information for gnutls is broken
> for the static linking case, and outputs --libs options which the
> compiler does not recognize. Work around this problem by testing
> that the --cflags/--libs output will at least allow compilation
> before enabling gnutls support.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Daniel P. Berrange <berrange@redhat.com>

Looks like a reasonable approach to me.

> ---
>  configure | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/configure b/configure
> index cc0338d..704b34c 100755
> --- a/configure
> +++ b/configure
> @@ -2116,10 +2116,26 @@ fi
>  ##########################################
>  # GNUTLS probe
>  
> +gnutls_works() {
> +    # Unfortunately some distros have bad pkg-config information for gnutls
> +    # such that it claims to exist but you get a compiler error if you try
> +    # to use the options returned by --libs. Specifically, Ubuntu for --static
> +    # builds doesn't work:
> +    # https://bugs.launchpad.net/ubuntu/+source/gnutls26/+bug/1478035
> +    #
> +    # So sanity check the cflags/libs before assuming gnutls can be used.
> +    if ! $pkg_config --exists "gnutls"; then
> +        return 1
> +    fi
> +
> +    write_c_skeleton
> +    compile_prog "$($pkg_config --cflags gnutls)" "$($pkg_config --libs gnutls)"
> +}
> +
>  gnutls_gcrypt=no
>  gnutls_nettle=no
>  if test "$gnutls" != "no"; then
> -    if $pkg_config --exists "gnutls"; then
> +    if gnutls_works; then
>          gnutls_cflags=`$pkg_config --cflags gnutls`
>          gnutls_libs=`$pkg_config --libs gnutls`
>          libs_softmmu="$gnutls_libs $libs_softmmu"

Regards,
Daniel
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