updated libpng to 1.5.4 - last link was broken.

[skinnyjames]

Updated libpng to 1.5.4

I ran into an error making the libgd libraries for libwmf-0.2.8.4 on OSX 10.5.8

Undefined symbols: "_png_check_sig", referenced from: _gdImageCreateFromPngCtx in libgd.a(gd_png.o) ld: symbol(s) not found collect2: ld returned 1 exit status make[2]: * [libwmf.la] Error 1 make[1]: * [check-recursive] Error 1 make: *\ [check-recursive] Error 1

Solved@http://www.bill.eccles.net/bills_words/2010/01/building-a-mac-os-x-server-106.html

the problem above is caused by the removal of the long-deprecated _png_check_sig from libpng as described in the release notes, here.

Changing line 139 in libwmf-0.2.8.4/src/extra/gd/gd_png.c from

     return NULL;                /\* bad signature */

to

     return NULL;   /* bad signature */
}```             

fixed the problem for me.