Comment 10 for bug 1581132

When building systemd with this kernel:

In file included from ../src/udev/net/ethtool-util.c:22:0:
/usr/include/linux/ethtool.h: In function ‘ethtool_validate_speed’:
/usr/include/linux/ethtool.h:1321:18: error: ‘INT_MAX’ undeclared (first use in this function)
  return speed <= INT_MAX || speed == SPEED_UNKNOWN;
                  ^
/usr/include/linux/ethtool.h:1321:18: note: each undeclared identifier is reported only once for each function it appears in

...I think you need to cherry-pick 14e2037902d65213842b4e40305ff54a64abbcb6