gcc-7-arm vendor branch

Hi, I would like to thank David Edelsohn for his help during the process of getting Amazon’s contributions to GCC covered by an FSF copyright assignment. As a first contribution, I would like to create a vendor branch for gcc-7 that will contain back-ported patches for Arm such as -moutline-atomic

[AArch64] Backporting -moutline-atomics to gcc 9.x and 8.x

Hi, is somebody already working on backporting -moutline-atomics to gcc 8.x and 9.x branches? Thanks, Sebastian