Building Emacs fails - downgraded libpng?

[holtzermann17@…]

After my attempt to build Emacs 24.3 from source failed, Eli Zaretski commented to me:

My crystal ball says that you somehow downgraded your libraries to a libpng version older than 1.5, while the headers are still for 1.5. These functions are needed by Emacs for libpng 1.5 or later.

Indeed,

sudo port uninstall libpng

shows that I had 4 versions installed (1.4.7_0, 1.4.8_0, 1.4.12_0, and 1.5.15_0 - which is designated as "active"). I uninstalled these earlier versions along with all libpng support that had been installed with fink -- but I still get the same error message when I try to build Emacs.

Undefined symbols:

"_png_longjmp", referenced from:

_my_png_error in image.o

"_png_set_longjmp_fn", referenced from:

_png_load_body in image.o

The Emacs bug report is here. ​http://lists.gnu.org/archive/html/bug-gnu-emacs/2013-04/msg00593.html