diff --git a/SystemTools.cxx b/SystemTools.cxx
index d01ec0a388be48812459f3a1d5d3e2cbc3035a4a..c883720762746da17aeef981213fed2adbf47cfc 100644
--- a/SystemTools.cxx
+++ b/SystemTools.cxx
@@ -25,8 +25,8 @@
 
 #include <ctype.h>
 #include <errno.h>
-#ifdef QNX /* TODO: Find real preprocessor for QNX. */
-# include <malloc.h> /* for malloc/free on some systems */
+#ifdef __QNX__
+# include <malloc.h> /* for malloc/free on QNX */
 #endif
 #include <stdio.h>
 #include <stdlib.h>