Use permissive classifications in `platformFromTriple`
Use permissive classifications in `platformFromTriple`

The `Permissive` classification is for recognising tokens from the
"outside world". `platformFromTriple` is similar to
`buildOS`/`buildArch`.

Specifically, on IBM AIX, the platform triple is usually
"powerpc-ibm-aix", where "powerpc" will only be recognised in
`Permissive` mode.

martinvlk/cabal,mydaum/cabal,Heather/cabal,themoritz/cabal,sopvop/cabal,bennofs/cabal,sopvop/cabal,lukexi/cabal,Heather/cabal,randen/cabal,gbaz/cabal,edsko/cabal,themoritz/cabal,kolmodin/cabal,randen/cabal,trskop/cabal,sopvop/cabal,headprogrammingczar/cabal,kolmodin/cabal,martinvlk/cabal,themoritz/cabal,thomie/cabal,garetxe/cabal,edsko/cabal,thomie/cabal,headprogrammingczar/cabal,mydaum/cabal,trskop/cabal,lukexi/cabal,bennofs/cabal,garetxe/cabal,gbaz/cabal