tidy up CALLCONV handling; make cc and hsc2hs defaults overrideable
tidy up CALLCONV handling; make cc and hsc2hs defaults overrideable
FranklinChen/Hugs,FranklinChen/Hugs,FranklinChen/Hugs,FranklinChen/Hugs,FranklinChen/Hugs,FranklinChen/Hugs,FranklinChen/Hugs