https://github.com/oetiker/rrdtool-1.x/issues/1012
--- rrdtool-1.7.2/tests/Makefile.in.old	2019-05-27 18:46:42.000000000 +0000
+++ rrdtool-1.7.2/tests/Makefile.in	2019-06-04 06:27:36.143871636 +0000
@@ -537,7 +537,7 @@
 top_builddir = @top_builddir@
 top_srcdir = @top_srcdir@
 TESTS = modify1 modify2 modify3 modify4 modify5 \
-	tune1 tune2 graph1 rpn1 rpn2 \
+	tune1 tune2 graph1 rpn1 \
 	rrdcreate \
 	dump-restore \
 	create-with-source-1 create-with-source-2 create-with-source-3 \
@@ -555,7 +555,7 @@
 	rrdcreate \
 	tune1-testa-mod1.dump tune1-testa-mod2.dump tune1-testorg.dump \
 	tune2-testa-mod1.dump tune2-testorg.dump \
-	valgrind-supressions dcounter1 dcounter1.output graph1.output vformatter1 rpn1.output rpn2.output \
+	valgrind-supressions dcounter1 dcounter1.output graph1.output vformatter1 rpn1.output \
 	xport1.json.output xport1.xml.output \
 	pdp-calc1 pdp-calc1-1-avg-60.output pdp-calc1-1-avg-300.output pdp-calc1-1-max-300.output
 
@@ -820,13 +820,6 @@
 	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
 	--log-file $$b.log --trs-file $$b.trs \
 	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
-	"$$tst" $(AM_TESTS_FD_REDIRECT)
-rpn2.log: rpn2
-	@p='rpn2'; \
-	b='rpn2'; \
-	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
-	--log-file $$b.log --trs-file $$b.trs \
-	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
 	"$$tst" $(AM_TESTS_FD_REDIRECT)
 rrdcreate.log: rrdcreate
 	@p='rrdcreate'; \