[metapost] Bug with simple number comparisons with new number systems

[Toby Thurston]

I'm getting strange results comparing numbers with the new number systems.

Consider this program:

    show 0.0001 < 0.001, numbersystem, mpversion; end.

With the default number system this gives

>> true
>> "scaled"
>> "1.999" )

on my log. But with the other number systems I get: 

>> true
>> "double"
>> "1.999" )

>> false
>> "binary"
>> "1.999" )

>> false
>> "decimal"
>> "1.999" )

which is a bit unexpected...

I'm using a version I compiled myself from source after you fixed the normaldeviate bug a couple of months ago.
Testing with V1.902, the only other version I have on hand, I only get the error with "decimal". But it does not appear to matter what numbers I use.  I get the same results  with "1<2", or "1/4<1/2", etc

This is MetaPost, version 1.902 (TeX Live 2014) (kpathsea version 6.2.0)
>> true
>> "scaled" )
This is MetaPost, version 1.902 (TeX Live 2014) (kpathsea version 6.2.0)
>> true
>> "double" )
This is MetaPost, version 1.902 (TeX Live 2014) (kpathsea version 6.2.0)
>> true
>> "binary" )
This is MetaPost, version 1.902 (TeX Live 2014) (kpathsea version 6.2.0)
>> false
>> "decimal" )

I've posted an entry on the tracker.  Toby