diff --git a/libs/pbd/enumwriter.cc b/libs/pbd/enumwriter.cc
index 0cfe42a0c3..243cd1c6ab 100644
--- a/libs/pbd/enumwriter.cc
+++ b/libs/pbd/enumwriter.cc
@@ -19,6 +19,7 @@
 */
 
 #include <cctype>
+#include <algorithm>
 
 #include <cstring>
 #include <cstdlib>