a small optimization to argvmods-to-mapping-rules converter
a small optimization to argvmods-to-mapping-rules converter

- split rules that begin with $ARCH or $MACHINE_ARCH to different
  rulesets; this reduces the number of rules that must
  be checked when mapping filenames in /usr/bin

OlegGirko/ldbox,h113331pp/scratchbox2,BinChengfei/scratchbox2,OlegGirko/ldbox,madscientist42/scratchbox2,loganchien/scratchbox2,OlegGirko/ldbox,lbt/scratchbox2,loganchien/scratchbox2,ldbox/ldbox,lbt/scratchbox2,h113331pp/scratchbox2,ldbox/ldbox,OlegGirko/ldbox,h113331pp/scratchbox2,loganchien/scratchbox2,lbt/scratchbox2,ldbox/ldbox,BinChengfei/scratchbox2,h113331pp/scratchbox2,ldbox/ldbox,loganchien/scratchbox2,h113331pp/scratchbox2,lbt/scratchbox2,madscientist42/scratchbox2,BinChengfei/scratchbox2,OlegGirko/ldbox,BinChengfei/scratchbox2,ldbox/ldbox,madscientist42/scratchbox2,ldbox/ldbox,h113331pp/scratchbox2,OlegGirko/ldbox,madscientist42/scratchbox2,madscientist42/scratchbox2,madscientist42/scratchbox2,loganchien/scratchbox2,lbt/scratchbox2,BinChengfei/scratchbox2,loganchien/scratchbox2,BinChengfei/scratchbox2