Re: PATCH: Check TLS for libgcc

[Paolo Bonzini <paolo dot bonzini at lu dot unisi dot ch>]

> Luckily, we can use GCC_CHECK_TLS for the native compiler of the
> native target.  Even if the build compiler doesn't support TLS, it
> won't be a problem.  The stage 2 and stage 3 libgcc will have proper
> TLS support if the stage 2 and stage 3 compilers do supprot TLS at
> run-time. During stage 3, the compiler checked by GCC_CHECK_TLS in
> gcc in this case is the stage 2 compiler, which should have the
> identical features as the stage 3 compiler, which will be used to
> compile stage 3 libgcc. So libgcc can use auto-host.h in gcc to check
> if TLS can be used for the native compiler of the native target.

My first choice would be to try wrapping the invocation in libgcc like this:

  if test $host = $build; then
    saved_CFLAGS=$CFLAGS saved_CC=$CC
    CC=$CC_FOR_BUILD CFLAGS=$CFLAGS_FOR_BUILD
  fi
  GCC_CHECK_TLS
  if test $host = $build; then
    CFLAGS=$saved_CFLAGS
    CC=$saved_CC
  fi

It should use the previous stage of as/ld/gcc instead of the current 
stage.  However, this is not true right now because CC_FOR_BUILD is not 
modified correctly.  I'll see if I can make a patch.

Paolo