[gdk-pixbuf/gdk-pixbuf-2-28] build: drop "libpng" from detected list

[Matthias Clasen <matthiasc src gnome org>]

commit 00df481177f59ebd578bef713be3f181122dddfa
Author: Richard Purdie <richard purdie linuxfoundation org>
Date:   Mon Apr 15 08:06:45 2013 -0400

    build: drop "libpng" from detected list
    
    This gives us an arbitrary version depending on the build root, and we
    may not be upwards compatible with future versions.  Or it's possible
    that the ancient (but LSB mandated) 1.2 claims the "libpng.pc" name.
    
    Signed-off-by: Colin Walters <walters verbum org>

 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/configure.ac b/configure.ac
index ed4aa28..152fbcb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -586,7 +586,7 @@ fi
 
 dnl Test for libpng
   if test x$with_libpng != xno && test -z "$LIBPNG"; then
-    for l in libpng16 libpng15 libpng14 libpng12 libpng13 libpng10 libpng; do
+    for l in libpng16 libpng15 libpng14 libpng12 libpng13 libpng10; do
       AC_MSG_CHECKING(for $l)
       if $PKG_CONFIG --exists $l ; then
         AC_MSG_RESULT(yes)