+checksym.awk => Used for maintaining pnglibconf.h
+def.dfn => Used for maintaining pnglibconf.h
+options.awk => Used for maintaining pnglibconf.h
+pnglibconf.dfa => Used for maintaining pnglibconf.h
+pnglibconf.mak => Used for maintaining pnglibconf.h
+sym.dfn => Used for symbol versioning
+symbols.def => Used for symbol versioning
+symbols.dfn => Used for symbol versioning
+vers.dfn => Used for symbol versioning
+
+