Workaround for broken cmpxchg8b inlining on ix86
    
    - Workaround for broken cmpxchg8b inlining on ix86
    - Don't use generic optimization on ix86
    - Increase memory up to 1024 mbytes while generating docs on non-ppc
    arches
    
    Signed-off-by: Peter Lemenkov <lemenkov@gmail.com>