Use pkg-config to report libpng version and installation directories.


diff -Naur libpng-1.2.31.orig/scripts/libpng-config.in libpng-1.2.31/scripts/libpng-config.in
--- libpng-1.2.31.orig/scripts/libpng-config.in	2008-05-29 13:37:58.000000000 -0400
+++ libpng-1.2.31/scripts/libpng-config.in	2008-08-23 16:57:20.000000000 -0400
@@ -8,11 +8,11 @@
 
 # Modeled after libxml-config.
 
-version="@PNGLIB_VERSION@"
-prefix="@prefix@"
-exec_prefix="@exec_prefix@"
-libdir="@libdir@"
-includedir="@includedir@/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@"
+version=`pkg-config --modversion libpng`
+prefix=`pkg-config --variable prefix libpng`
+exec_prefix=`pkg-config --variable exec_prefix libpng`
+libdir=`pkg-config --variable libdir libpng`
+includedir=`pkg-config --variable includedir libpng`
 libs="-lpng@PNGLIB_MAJOR@@PNGLIB_MINOR@"
 all_libs="-lpng@PNGLIB_MAJOR@@PNGLIB_MINOR@ @LIBS@"
 I_opts="-I${includedir}"