bcrypt: Ensure we have gnutls_hash() available.

[Sebastian Lackner]

On 18.01.2016 12:41, Huw Davies wrote:
> Fixes compile failures with older versions of gnutls.
> 
> Signed-off-by: Huw Davies <huw at codeweavers.com>
> ---
>  configure.ac              |  1 +
>  dlls/bcrypt/bcrypt_main.c | 10 +++++-----
>  2 files changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/configure.ac b/configure.ac
> index 0766edf..0eedf43 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -1270,6 +1270,7 @@ then
>  #include <gnutls/crypto.h>]], [[static typeof(gnutls_mac_get_key_size) *func; if (func) return 0;]])],
>                  [WINE_CHECK_SONAME(gnutls,gnutls_global_init,,[GNUTLS_CFLAGS=""],[$GNUTLS_LIBS],[[libgnutls\\(-deb0\\)\\{0,1\\}]])])],
>              [GNUTLS_CFLAGS=""])])
> +    WINE_CHECK_LIB_FUNCS(gnutls_hash,[$GNUTLS_LIBS])
>  fi
>  WINE_WARNING_WITH(gnutls,[test "x$ac_cv_lib_soname_gnutls" = "x"],
>                   [libgnutls ${notice_platform}development files not found, no schannel support.])

Wouldn't it be useful to warn a bit more explicit at compile-time? Otherwise packagers will
have a hard time to find out if its supported by their build.