Revert "Revert "Break out common compile flags""
Revert "Revert "Break out common compile flags""

This reverts commit 45e1067502da0c3cbf77d8b6aafc9d17b461cea3

Change-Id: I00e7bb9dd02287db868bc291e25d27066fc486da
Reviewed-on: https://gerrit.chromium.org/gerrit/11746
Reviewed-by: Randall Spangler <62698fdbb84d1779579ee80c3f39fac22017e5bc@chromium.org>
Commit-Ready: Simon Glass <c00b0378376498bd9cd974c388df8854c0131d27@chromium.org>
Tested-by: Simon Glass <c00b0378376498bd9cd974c388df8854c0131d27@chromium.org>

geekboxzone/mmallow_external_vboot_reference,coreboot/vboot,acorn-marvell/vboot_reference,ccaapton/vboot_reference,ccaapton/vboot_reference,acorn-marvell/vboot_reference,ionave/seismograph,ionave/seismograph,geekboxzone/mmallow_external_vboot_reference,geekboxzone/mmallow_external_vboot_reference,ccaapton/vboot_reference,geekboxzone/mmallow_external_vboot_reference,ccaapton/vboot_reference,acorn-marvell/vboot_reference,coreboot/vboot,geekboxzone/mmallow_external_vboot_reference,coreboot/vboot,coreboot/vboot,ionave/seismograph,marineam/seismograph,marineam/seismograph,coreboot/vboot,acorn-marvell/vboot_reference,marineam/seismograph,marineam/seismograph