winegcc: Use --safeseh winebuild option on msvc target.

lld-link requires all x86 object files to be SEH compatible unless it's
explicitly disabled.

Signed-off-by: Jacek Caban <jacek@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>

tools/winegcc/winegcc.c

@@ -1250,6 +1250,8 @@ static void build(struct options* opts)
         if (opts->large_address_aware) strarray_add( spec_args, "--large-address-aware" );
     }
 
+    if (opts->target_platform == PLATFORM_WINDOWS) strarray_add(spec_args, "--safeseh");
+
     if (entry_point)
     {
         strarray_add(spec_args, "--entry");