Fix PR target/53440 - handle generic thunks better for TARGET_32BIT.

Fix PR target/53440 - handle generic thunks better for TARGET_32BIT.

This partially fixes PR target/53440 atleast in ARM and
Thumb2 state. I haven't yet managed to get my head around
rewriting the Thumb1 support yet.

Tested on armhf with a bootstrap and regression test
with no regressions.

Queued for stage1 now as it isn't technically a regression.

regards
Ramana

2016-05-13  Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>

        PR target/53440
        * config/arm/arm.c (arm32_output_mi_thunk): New.
        (arm_output_mi_thunk): Rename to arm_thumb1_mi_thunk. Rework
        to split Thumb1 vs TARGET_32BIT functionality.
        (arm_thumb1_mi_thunk): New.

        * g++.dg/inherit/thunk1.C: Support arm / aarch64.

From-SVN: r236198