--- cinepaint-0.21-2-orig/plug-ins/pdf/pdf.cpp 
+++ cinepaint-0.21-2/plug-ins/pdf/pdf.cpp 
@@ -50,6 +50,8 @@
 #include <oyranos/oyranos.h>
 #endif
 }
+
+#include <cstring>            // strcmp(), strlen(), strrchr()
 
 // Declare some local functions: