[OpenJDK 2D-Dev] Use of obsolete png_check_sig function in splashscreen_png.c

[Phil Race]

 From http://www.libpng.org/pub/png/libpng.html

 >The current public release, *libpng 1.4.2*, restores the 1.2.x 
png_check_sig() macro ...

I suppose removing it caused too many problems.

So whilst I see nothing wrong with this change, I wonder if its worth 
the trouble ?

If you still want to push I'll supply a bug id.

2 other things
1) Not that it  matters (just FYI) but splashscreen is considered to be 
AWT not 2D,
even though libpng itself is 2D. Relevant only because the bug would be 
classes_awt,
not classes_2d.
2) Maybe we are due to upgrade the libpng in JDK ? We upgraded it
last in May  2007 right before launching openjdk, then to 1.2.18
Was there ever a 1.3.X ?? Looks like that got skipped for some reason.
Doesn't seem urgent but it might be a good thing to add to the to-do list.

-phil.

Andrew John Hughes wrote:
> With libpng 1.4, the png_check_sig function has been removed, having
> been deprecated in previous releases:
>
> http://www.libpng.org/pub/png/src/libpng-1.2.x-to-1.4.x-summary.txt
>
> This function is used in splashscreen_png.c and can be easily be
> replaced with png_sig_cmp, as in this webrev:
>
> http://cr.openjdk.java.net/~andrew/libpng/webrev.01/
>
> This actually makes the line clearer as the not operator is no longer needed.
> I know OpenJDK still uses an in-tree libpng 1.2 by default, but this
> fix still works with that version and also means that the code will
> still build, should the internal libpng be upgraded to 1.4.
>
> Ok to push this?  If so, can I have a bug ID for it?
>
> Thanks,
>