--- a/classic-bugs/vol1/Makefile
+++ b/classic-bugs/vol1/Makefile
@@ -1,13 +1,13 @@
 JAGS = /usr/local/bin/jags
 TIME = /usr/bin/time
-EXDIRS = blocker bones dyes epil equiv kidney leuk line litters mice pump \
+EXAMPLES ?= blocker bones dyes epil equiv kidney leuk line litters mice pump \
          rats salm seeds oxford lsat
 
 all:
 
 bench:
 	@echo "Creating new benchmark results"
-	@for d in $(EXDIRS); do \
+	@for d in $(EXAMPLES); do \
 	    (echo $${d}; \
 	    cd $${d}; \
 	    for cmdfile in `ls test*.cmd`; do \
@@ -20,7 +20,7 @@
 
 check: clean
 	@echo "Checking output against benchmark results"
-	@for d in $(EXDIRS); do \
+	@for d in $(EXAMPLES); do \
 	   (cd $${d} && \
 	    for cmdfile in `ls test*.cmd`; do \
 	      (cp bench-$${cmdfile%%.cmd}.R bench.R &&  \
@@ -32,7 +32,7 @@
 
 checktime:
 	rm -f times
-	@for d in $(EXDIRS); do \
+	@for d in $(EXAMPLES); do \
 	   (cd $${d} && \
 	    for cmdfile in `ls test*.cmd`; do \
 	      ($(TIME)  -f "$${d} $${cmdfile} %e %U %S" -o ../times -a \
@@ -41,12 +41,13 @@
 	done;
 
 clean:
-	@for d in $(EXDIRS); do \
+	@for d in $(EXAMPLES); do \
 	   (cd $${d} && rm -f core jags.out jags.ind jags.dump \
             CODAchain*.txt CODAindex.txt gmon.out) || exit 1; \
 	done;
 
 distclean: clean
-	@for d in $(EXDIRS); do \
+	@for d in $(EXAMPLES); do \
 	   (cd $${d} && rm -f bench-*.R) || exit 1; \
 	done;
+