cairo fails to build.

[Peter B. West]

lydia:Downloads pbw$ sudo port install cairo
--->  Computing dependencies for cairo
--->  Building cairo
Error: Target org.macports.build returned: shell command " cd "/opt/ 
local/var/macports/build/ 
_opt_local_var_macports_sources_rsync.macports.org_release_ports_graphics_cairo 
/work/cairo-1.8.8" && /usr/bin/make -j2 all " returned error 2
Command output:   "_png_get_error_ptr", referenced from:
      _png_simple_warning_callback in cairo-png.o
      _png_simple_error_callback in cairo-png.o
      _stream_read_func in cairo-png.o
      _stream_write_func in cairo-png.o
      _stdio_read_func in cairo-png.o
      _stdio_write_func in cairo-png.o
  "_png_create_write_struct", referenced from:
      _write_png in cairo-png.o
  "_png_destroy_read_struct", referenced from:
      _read_png in cairo-png.o
  "_png_create_info_struct", referenced from:
      _read_png in cairo-png.o
      _write_png in cairo-png.o
  "_png_get_io_ptr", referenced from:
      _stream_read_func in cairo-png.o
      _stream_write_func in cairo-png.o
      _stdio_read_func in cairo-png.o
      _stdio_write_func in cairo-png.o
  "_png_set_read_user_transform_fn", referenced from:
      _read_png in cairo-png.o
      _read_png in cairo-png.o
  "_png_read_image", referenced from:
      _read_png in cairo-png.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
make[3]: *** [libcairo.la] Error 1
make[2]: *** [all] Error 2
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2

Error: Status 1 encountered during processing.