Revert "Add strict_aliasing."

This reverts commit 96536efedc2787754da5c7e11dc95f7c85e30f58.
Revert "GCC 4.7 O3 and aliasing Optimizations"

This reverts commit aec2ce932785cbac4ab498310f0c7c17426b5fcc.
Revert "Use GCC 4.7 from google"

This reverts commit 19c2b94c28547e98c1f0d46889513fa64207de79.
Revert "x86: enable FORTIFY_SOURCE"

This reverts commit a322d7ea1061962531516cfe3eab20256badd7bd.
Revert "Export TARGET_GCC_VERSION as an env variable."

This reverts commit 21d81624680c95b0d7dd42f5bd2a40c37d231dc4.
Revert "[ARM] Extend the usage of TARGET_GCC_VERSION for gdb and arm-eabi-*."

This reverts commit 96f864c2346c370186b7c72527c6d47a17df4815.
Revert "Add TARGET_GCC_VERSION"

This reverts commit 3469af48c6094e8df1020f6eedf4e30c104106aa.