[libpng16] Corrected Android builds and corrected libpng.vers with symbol

    prefixing This adds an API to set optimization options externally,
    providing an alternative and general solution for the non-portable
    run-time tests used by the ARM Neon code.  It also makes those tests
    compile and link on Android.
  The order of settings vs options in pnglibconf.h is reversed to allow
    settings to depend on options and options can now set (or override) the
    defaults for settings.
diff --git a/png.c b/png.c
index 0fd1e98..d58b3fd 100644
--- a/png.c
+++ b/png.c
@@ -768,13 +768,13 @@
 #else
 #  ifdef __STDC__
    return PNG_STRING_NEWLINE \
-     "libpng version 1.6.1beta06 - March 2, 2013" PNG_STRING_NEWLINE \
+     "libpng version 1.6.1beta06 - March 4, 2013" PNG_STRING_NEWLINE \
      "Copyright (c) 1998-2013 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
      "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
      "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
      PNG_STRING_NEWLINE;
 #  else
-      return "libpng version 1.6.1beta06 - March 2, 2013\
+      return "libpng version 1.6.1beta06 - March 4, 2013\
       Copyright (c) 1998-2013 Glenn Randers-Pehrson\
       Copyright (c) 1996-1997 Andreas Dilger\
       Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
@@ -4012,6 +4012,27 @@
 }
 #endif /* READ_GAMMA */
 
+/* HARDWARE OPTION SUPPORT */
+#ifdef PNG_SET_OPTION_SUPPORTED
+int PNGAPI
+png_set_option(png_structrp png_ptr, int option, int onoff)
+{
+   if (png_ptr != NULL && option >= 0 && option < PNG_OPTION_NEXT &&
+      (option & 1) == 0)
+   {
+      int mask = 3 << option;
+      int setting = (2 + (onoff != 0)) << option;
+      int current = png_ptr->options;
+
+      png_ptr->options = (png_byte)((current & ~mask) | setting);
+
+      return (current & mask) >> option;
+   }
+
+   return PNG_OPTION_INVALID;
+}
+#endif
+
 /* sRGB support */
 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)