Add wrapper for strtoll() function. Include unit tests.
Signed-off-by: NCarlos L. Torres <carlos.torres@rackspace.com>
Message-Id: <7454a6bb9ec03b629e8beb4f109dd30dc2c9804c.1437346779.git.carlos.torres@rackspace.com>
[Use int64_t in prototype, since that's what QEMU uses. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>