Otherwise "$(A) $(B)" will not be equal to "" even if A and B are empty.
Trac #856.
# -----------------------------------------------------------------------------
# RTS ways
# -----------------------------------------------------------------------------
# RTS ways
-WAYS=$(GhcLibWays) $(GhcRTSWays)
+WAYS=$(strip $(GhcLibWays) $(GhcRTSWays))
ifneq "$(findstring debug, $(way))" ""
GhcRtsHcOpts=
ifneq "$(findstring debug, $(way))" ""
GhcRtsHcOpts=