diff --git a/comphelper/qa/makefile.mk b/comphelper/qa/makefile.mk
index 972b0a87e0b5..9c86c24a20bf 100644
--- a/comphelper/qa/makefile.mk
+++ b/comphelper/qa/makefile.mk
@@ -33,6 +33,13 @@ ENABLE_EXCEPTIONS := TRUE
 
 .INCLUDE: settings.mk
 
+#building with stlport, but cppunit was not built with stlport
+.IF "$(USE_SYSTEM_STL)"!="YES"
+.IF "$(SYSTEM_CPPUNIT)"=="YES"
+CFLAGSCXX+=-DADAPT_EXT_STL
+.ENDIF
+.ENDIF
+
 CFLAGSCXX += $(CPPUNIT_CFLAGS)
 
 DLLPRE = # no leading "lib" on .so files