since we are using png functions directly, we have to link against libpng explicitly

diff --git a/configure.ac b/configure.ac
index 353696fe4fb4f4f183df8ba8089b02a52ed017a2..3fabcf4f4adb7b7a8f032f9345d9fbfd3d808aa0 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -600,7 +600,7 @@ CORE_LIBS="$LIBS"
 
 if test $enable_rrd_graph != no; then
 dnl EX_CHECK_ALL(z,          zlibVersion,               zlib.h,                 zlib,        1.2.5,  http://zlib.net/, "")
-dnl EX_CHECK_ALL(png,        png_access_version_number, png.h,                  libpng,      1.4.8,  ftp://ftp.simplesystems.org/pub/libpng/png/src/, "")
+EX_CHECK_ALL(png,        png_access_version_number, png.h,                  libpng,      1.4.8,  ftp://ftp.simplesystems.org/pub/libpng/png/src/, "")
 dnl EX_CHECK_ALL(freetype,   FT_Init_FreeType,          ft2build.h,            freetype2,   2.4.6,  http://download.savannah.gnu.org/releases/freetype/, /usr/include/freetype2)
 dnl EX_CHECK_ALL(fontconfig, FcInit,                    fontconfig.h,          fontconfig,  2.8.0,  http://www.freedesktop.org/software/fontconfig/release/, /usr/include)
 dnl EX_CHECK_ALL(cairo,      cairo_font_options_create,     cairo.h,                cairo-png,   1.10.2,  http://cairographics.org/releases/, "")