+else
+
+include/surf/surfxml.h surf/surfxml.l: surf/surfxml.dtd
+ @echo "ERROR: src/surf/surfxml.dtd was modified, but the flexml program was not detected"
+ @echo "ERROR: Please install it, or if you didn't modify this file, try this:"
+ @echo "ERROR: touch src/include/surf/surfxml.h src/surf/surfxml.l"
+ @exit 1
+endif