misc: Wrap __attribute__((aligned())) in a macro in compiler.hh.

This attribute is gcc specific (also implemented by clang for
compatibility), and so should be behind a level of abstraction to make
using different compilers easier.

Change-Id: I7495f011f617268dd7a589dc0bcf1b3b7f515046
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/35976
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
4 files changed