Add metatests for mutex usage

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 5f5d2fd..04626c3 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -1925,7 +1925,7 @@
     programs/test/cpp_dummy_build
 
     msg "test: metatests (clang)"
-    tests/scripts/run-metatests.sh any
+    tests/scripts/run-metatests.sh any pthread
 
     msg "program demos (full config, clang)" # ~10s
     tests/scripts/run_demos.py