diff --git a/config.tests/common/alloca/alloca.cpp b/config.tests/common/alloca/alloca.cpp
index 566ee5651a..d839b381ef 100644
--- a/config.tests/common/alloca/alloca.cpp
+++ b/config.tests/common/alloca/alloca.cpp
@@ -39,6 +39,9 @@
 
 #include <alloca.h>
 
+// extra include needed in QNX7 to define NULL for the alloca() macro
+#include <stdlib.h>
+
 int main(int, char **)
 {
     alloca(1);