[Bug libstdc++/35816] New: libstdc++ built during bootstrap is pulling in host g++ support for atomic builtins

["oblivian at users dot sourceforge dot net" <gcc-bugzilla@gcc.gnu.org>]

When compiling a combined gcc + g++ + binutils, the configure script for the
libstdc++ library is using the host g++ rather than the last stage g++ for
determining atomic builtin support status.

While I probably need to compile the toolchain with CXXFLAGS=-march=i486, from
what I've read, to enable support for atomic builtins in the compiler, I did
not.  This resulted in a target g++ that did not support atomic builtins and a
libstdc++ that expected the compiler did because it got the value from checking
the host g++ rather than the final bootstrap stage g++.

The configure parameters were:
  --prefix=/$(TOOLS_DIR)/usr \
  --with-sysroot=/$(TOOLS_DIR) \
  --with-pic \
  --enable-shared \
  --enable-clocale=gnu \
  --enable-threads=posix \
  --enable-__cxa_atexit \
  --enable-languages=c,c++ \
  --enable-checking=release \
  --disable-werror \
  --enable-stage1-checking \
  --enable-bootstrap


-- 
           Summary: libstdc++ built during bootstrap is pulling in host g++
                    support for atomic builtins
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: oblivian at users dot sourceforge dot net


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35816