host-utils: introduce uabs64()

host-utils: introduce uabs64()

Introduce uabs64(), a function that returns the absolute value of
a 64-bit int as an unsigned value. This avoids the undefined behavior
for common abs implementations, where abs of the most negative value is
undefined.

Signed-off-by: Luis Pires <luis.pires@eldorado.org.br>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20210910112624.72748-4-luis.pires@eldorado.org.br>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>