give 'runhaskell' the 'exeext' treatment too
# Only install runhaskell if there isn't already one installed
ifneq "$(findstring install, $(MAKECMDGOALS))" ""
ifeq "$(wildcard $(bindir)/runhaskell)" ""
# Only install runhaskell if there isn't already one installed
ifneq "$(findstring install, $(MAKECMDGOALS))" ""
ifeq "$(wildcard $(bindir)/runhaskell)" ""
-INSTALL_PROGS += runhaskell
+INSTALL_PROGS += runhaskell$(exeext)