diff -ur matplotlib-2.2.2/src/_png.cpp host/matplotlib-2.2.2/src/_png.cpp
--- matplotlib-2.2.2/src/_png.cpp	2018-03-17 14:03:23.000000000 -0400
+++ host/matplotlib-2.2.2/src/_png.cpp	2018-05-16 17:37:38.065033586 -0400
@@ -774,6 +774,10 @@
             INITERROR;
         }

+        volatile long x;
+        x = (long)malloc(0);
+        free((void*)x);
+
         import_array();

         if (PyModule_AddIntConstant(m, "PNG_FILTER_NONE", PNG_FILTER_NONE) ||