test: make sure rdbg tests exit with a code > 0 when failing

test/Makefile.inc

-# Time-stamp: <modified the 25/01/2023 (at 11:01) by Erwan Jahier>
+# Time-stamp: <modified the 29/01/2023 (at 16:21) by Erwan Jahier>
 #
 # Define some default rules that ought to work most of the time
 #
@@ -106,7 +106,9 @@ endif
 	ledit -h rdbg-history -x rdbg --sasa -sut "sasa $* $(DAEMON)"  -l 10000
 
 %.rdbg-test: %.cma
-	rdbg --sasa -sut "sasa $*.dot $(DAEMON)" -go --input some_session -l 10000
+	rdbg --sasa -sut "sasa $*.dot $(DAEMON)" -go --input some_session -l 10000 \
+		| grep Error > $*.rdbg-test.log && echo "Error: 'make $@' failed" \
+		  && cat $*.rdbg-test.log && exit 2  || echo "'make $@' suceeds"
 
 %.rdbgui: %.cma
-	rdbgui4sasa -sut "sasa $*.dot $(DAEMON)"  -l 10000
+	ledit -h rdbg-history -x rdbgui4sasa -sut "sasa $*.dot"  -l 10000