Revise ANNOUNCE to reflect conditional compile of png_read_finish_row().

ANNOUNCE

@@ -54,8 +54,8 @@ version 1.2.37beta01 [May 14, 2009]
 version 1.2.37beta02 [May 18, 2009]
   Fixed typo in libpng documentation (FILTER_AVE should be FILTER_AVG)
   Relocated misplaced #endif in pngwrite.c, sCAL chunk handler.
-  Conditionally png_read_finish_row() which is not used by progressive
-     readers.
+  Conditionally compile png_read_finish_row() which is not used by
+    progressive readers.
 
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