diff --git a/libs/pbd/debug.cc b/libs/pbd/debug.cc
index 7fe7a1b90b..a6ff1dda56 100644
--- a/libs/pbd/debug.cc
+++ b/libs/pbd/debug.cc
@@ -20,6 +20,7 @@
  */
 
 #include <cstring>
+#include <cstdio>
 #include <cstdlib>
 #include <iostream>
 #include <map>