--- interpreter/Makefile.orig	2019-09-10 10:35:21.565863000 -0600
+++ interpreter/Makefile	2019-09-10 10:39:30.048331000 -0600
@@ -70,7 +70,7 @@
 
 .INTERMEDIATE:	$(LIB).mlpack
 $(LIB).mlpack:	$(DIRS)
-		ls $(DIRS:%=%/*.ml*) \
+		find $(DIRS) -depth 1 -name '*.ml' -or -name '*.ml?' \
 		| sed 's:\(.*/\)\{0,1\}\(.*\)\.[^\.]*:\2:' \
 		| grep -v main \
 		| sort | uniq \