Fix SmallInt representation for the minimal nativeint
Fix SmallInt representation for the minimal nativeint

* Minimal nativeint has no positive equivalent
* Fix #119

dianacgr/mozart2,mozart/mozart2,dianacgr/mozart2,eregon/mozart2,layus/mozart2,dianacgr/mozart2,Angeldude/mozart2,Angeldude/mozart2,mozart/mozart2,yjaradin/mozart2,yjaradin/mozart2,layus/mozart2,yjaradin/mozart2,mozart/mozart2,eregon/mozart2,layus/mozart2,eregon/mozart2,Angeldude/mozart2