Add reproducer from issue 2562

cpp_thread_test/Makefile

@@ -1,6 +1,6 @@
 include ../Makefile.rule
 
-all :: dgemv_tester dgemm_tester
+all :: dgemv_tester dgemm_tester dpotrf_bug2562
 
 dgemv_tester :
 	$(CXX) $(COMMON_OPT) -Wall -Wextra -Wshadow -fopenmp -std=c++11 dgemv_thread_safety.cpp ../libopenblas.a -lpthread -o dgemv_tester
@@ -10,5 +10,9 @@ dgemm_tester : dgemv_tester
 	$(CXX) $(COMMON_OPT) -Wall -Wextra -Wshadow -fopenmp -std=c++11 dgemm_thread_safety.cpp ../libopenblas.a -lpthread -o dgemm_tester
 	./dgemm_tester
 
+dpotrf_bug2562 : dgemv_tester
+	$(CXX) $(COMMON_OPT) -Wall -Wextra -Wshadow  -std=c++11 dpotrf_bug2562.cpp ../libopenblas.a -lpthread -o dpotrf_bug2562
+	./dpotrf_bug2562
+
 clean ::
 	rm -f dgemv_tester dgemm_tester