[RFA] Fix libstdc++ configure failure on cross-builds

[Joseph S. Myers]

On Fri, 3 Dec 2010, Paul Koning wrote:

> Index: gcc-4.5.1/libtool.m4
> ===================================================================
> --- gcc-4.5.1/libtool.m4	(revision 147400)
> +++ gcc-4.5.1/libtool.m4	(working copy)
> @@ -1715,6 +1715,11 @@
>      lt_cv_dlopen_self=yes
>      ;;
>  
> +  netbsd*)
> +    lt_cv_dlopen="dlopen"
> +    lt_cv_dlopen_libs=
> +    ;;
> +

libtool patches need to go to upstream libtool first.  Is this a backport 
from upstream?

> @@ -230,7 +230,8 @@
>        glibcxx_have_gc_sections=yes
>      fi
>    fi
> -  if test "$glibcxx_have_gc_sections" = "yes"; then
> +  if test "$glibcxx_have_gc_sections" = "yes" &&
> +	test x$gcc_no_link != xyes; then

Please explain why this is needed for your target when it isn't needed 
by other people building for bare-metal targets that cannot link at this 
point.

(In any case, I think NetBSD, like GNU/Linux, *should* be a target where 
building libstdc++ requires the ability to run link tests.  That is, you 
should need to build libc in your sysroot with a C-only compiler before 
building one supporting C++, and all the AC_DEFINE settings in 
crossconfig.m4 for particular functions should be replaced with calls to 
the appropriate configure test macros.)

-- 
Joseph S. Myers
joseph@codesourcery.com