add a tsan example

debian/qualify-clang.sh

@@ -510,6 +510,40 @@ int main(int argc, char **argv)
 clang-$VERSION -fsanitize=address foo.c -o foo -lc
 ./foo &> /dev/null || true
 
+echo '
+#include <pthread.h>
+#include <stdio.h>
+
+int Global;
+
+void *Thread1(void *x) {
+  Global++;
+  return NULL;
+}
+
+void *Thread2(void *x) {
+  Global--;
+  return NULL;
+}
+
+int main() {
+  pthread_t t[2];
+  pthread_create(&t[0], NULL, Thread1, NULL);
+  pthread_create(&t[1], NULL, Thread2, NULL);
+  pthread_join(t[0], NULL);
+  pthread_join(t[1], NULL);
+} ' > foo.c
+
+clang-$VERSION -o foo -fsanitize=thread -g -O1 foo.c
+if ! strings ./foo 2>&1 | grep -q "tsan"; then
+    echo "binary doesn't contain tsan code"
+    strings foo
+    exit 42
+fi
+if ! ./foo 2>&1 | grep -q "data race"; then
+    echo "sanitize=address is failing"
+    exit 42
+fi
 
 echo '
 class a {