Revised fix for bug 3111 - switch to usrt4_0.lib, which is exported unconditionally
usrt3_1.lib is invisibly exported by an FLM, so in platform builds this failed with "No rule to make usrt3_1.dso"
EXPORTS
_Z17VariantInitialisev @ 1 NONAME
_ZN7Variant10PowerResetEv @ 2 NONAME
_ZN7Variant14BaseLinAddressEv @ 3 NONAME
_ZN7Variant16MarkDebugPortOffEv @ 4 NONAME
_ZN7Variant8SwitchesEv @ 5 NONAME
_ZN7Variant8UartInitEv @ 6 NONAME