Re: [patch] Update build flags for new compiler feature

[Dave Korn <dave dot korn dot cygwin at googlemail dot com>]

Corinna Vinschen wrote:

> I just built a gcc 4.3.4 Linux->Cygwin cross compiler using the sources
> from the Cygwin 1.7 distro.  I used the following build flags:
> 
>   --disable-bootstrap --enable-version-specific-runtime-libs \
>   --enable-static --enable-shared --enable-shared-libgcc \
>   --disable-__cxa_atexit --with-gnu-ld --with-gnu-as --with-dwarf2 \
>   --disable-sjlj-exceptions --enable-languages=c,c++ --disable-symvers \
>   --enable-threads=posix --with-arch=i686 --with-tune=generic \
>   --with-newlib
    ^^^^^^^^^^^^^^

  Are you doing something tricky w.r.t. the headers and libs you supply to the
build process?  You appear to be using none-at-all out of --with-headers,
--with-includes and --with-sysroot.

> When I try to build Cygwin I get:
> 
>   cc1plus: error: command line option '-muse-libstdc-wrappers' is not
>   supported by this configuration
> 
> What am I doing wrong?

  Take a look in $objdir/gcc/config.log; what happened during the "checking
for __wrap__Znaj" test?  Hmmmmm, I may have the config set up wrong so it only
works in bootstrap, not crossbuilds.  You could try manually hacking
"-DUSE_CYGWIN_LIBSTDCXX_WRAPPERS=1" into the CFLAGS.  Meanwhile, I need to go
figure out how to make sure and check the target rather than host libraries
for the presence of a function.  (It's worth adding fixing this to the to-do
list for -2).

    cheers,
      DaveK