factor native PNG export out of file.cpp in preparation for new export dialog

diff --git a/src/selection-chemistry.cpp b/src/selection-chemistry.cpp
index 626199cda534a7b0254b2fe018845d723517f887..3d8b5c5aa830fc2bd39aa5a2b9ac121d672bbdd2 100644 (file)
--- a/src/selection-chemistry.cpp
+++ b/src/selection-chemistry.cpp
@@ -65,6 +65,7 @@
 #include "sp-clippath.h"
 #include "sp-mask.h"
 #include "file.h"
+#include "helper/png-write.h"
 #include "layer-fns.h"
 #include "context-fns.h"
 #include <map>