meson: assume x86-64-v2 baseline ISA

x86-64-v2 processors were released in 2008, assume that we have one.
Unfortunately there is no GCC flag to enable all the features
without disabling what came after; so enable them one by one.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 file changed