diff --git a/libs/ptformat/ptformat.cc b/libs/ptformat/ptformat.cc
index b6b13b745f..26381a6a90 100644
--- a/libs/ptformat/ptformat.cc
+++ b/libs/ptformat/ptformat.cc
@@ -29,6 +29,7 @@
 #ifdef HAVE_GLIB
 # include <glib/gstdio.h>
 # define ptf_open	g_fopen
+# define strndup	g_strndup
 #else
 # define ptf_open	fopen
 #endif