if test $enable_rrd_graph != no; then
+ ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+ EX_CHECK_STATE=NO
+ ex_check_save_LIBS=${LIBS}
+ ex_check_save_CPPFLAGS=${CPPFLAGS}
+ ex_check_save_LDFLAGS=${LDFLAGS}
+ if test "x""" != "x"; then
+ CPPFLAGS="$CPPFLAGS -I"""
+ fi
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking for png_access_version_number in -lpng" >&5
+$as_echo_n "checking for png_access_version_number in -lpng... " >&6; }
+if ${ac_cv_lib_png_png_access_version_number+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ ac_check_lib_save_LIBS=$LIBS
+LIBS="-lpng $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+
+/* Override any GCC internal prototype to avoid an error.
+ Use char because int might match the return type of a GCC
+ builtin and then its argument prototype would still apply. */
+#ifdef __cplusplus
+extern "C"
+#endif
+char png_access_version_number ();
+int
+main ()
+{
+return png_access_version_number ();
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+ ac_cv_lib_png_png_access_version_number=yes
+else
+ ac_cv_lib_png_png_access_version_number=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_png_png_access_version_number" >&5
+$as_echo "$ac_cv_lib_png_png_access_version_number" >&6; }
+if test "x$ac_cv_lib_png_png_access_version_number" = xyes; then :
+
+ ac_fn_c_check_header_mongrel "$LINENO" "png.h" "ac_cv_header_png_h" "$ac_includes_default"
+if test "x$ac_cv_header_png_h" = xyes; then :
+ LIBS="-lpng ${LIBS}";EX_CHECK_STATE=YES
+fi
+
+
+fi
+
+ if test $EX_CHECK_STATE = NO; then
+ for ac_prog in pkg-config
+do
+ # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_PKGCONFIG+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ if test -n "$PKGCONFIG"; then
+ ac_cv_prog_PKGCONFIG="$PKGCONFIG" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+ IFS=$as_save_IFS
+ test -z "$as_dir" && as_dir=.
+ for ac_exec_ext in '' $ac_executable_extensions; do
+ if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+ ac_cv_prog_PKGCONFIG="$ac_prog"
+ $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+ break 2
+ fi
+done
+ done
+IFS=$as_save_IFS
+
+fi
+fi
+PKGCONFIG=$ac_cv_prog_PKGCONFIG
+if test -n "$PKGCONFIG"; then
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: $PKGCONFIG" >&5
+$as_echo "$PKGCONFIG" >&6; }
+else
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+ test -n "$PKGCONFIG" && break
+done
+test -n "$PKGCONFIG" || PKGCONFIG="no"
+
+ if test "$PKGCONFIG" != "no"; then
+ if $PKGCONFIG --exists libpng; then
+ CPPFLAGS=${CPPFLAGS}" "`$PKGCONFIG --cflags libpng`
+ LDFLAGS=${LDFLAGS}" "`$PKGCONFIG --libs-only-L libpng`
+ LDFLAGS=${LDFLAGS}" "`$PKGCONFIG --libs-only-other libpng`
+ LIBS=${LIBS}" "`$PKGCONFIG --libs-only-l libpng`
+ unset ac_cv_lib_`echo png | sed 's/[^_a-zA-Z0-9]/_/g;s/^[0-9]/_/'`_png_access_version_number
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking for png_access_version_number in -lpng" >&5
+$as_echo_n "checking for png_access_version_number in -lpng... " >&6; }
+if ${ac_cv_lib_png_png_access_version_number+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ ac_check_lib_save_LIBS=$LIBS
+LIBS="-lpng $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+
+/* Override any GCC internal prototype to avoid an error.
+ Use char because int might match the return type of a GCC
+ builtin and then its argument prototype would still apply. */
+#ifdef __cplusplus
+extern "C"
+#endif
+char png_access_version_number ();
+int
+main ()
+{
+return png_access_version_number ();
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+ ac_cv_lib_png_png_access_version_number=yes
+else
+ ac_cv_lib_png_png_access_version_number=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_png_png_access_version_number" >&5
+$as_echo "$ac_cv_lib_png_png_access_version_number" >&6; }
+if test "x$ac_cv_lib_png_png_access_version_number" = xyes; then :
+
+ unset ac_cv_header_`echo png.h | sed 's/[^_a-zA-Z0-9]/_/g;s/^[0-9]/_/'`
+ ac_fn_c_check_header_mongrel "$LINENO" "png.h" "ac_cv_header_png_h" "$ac_includes_default"
+if test "x$ac_cv_header_png_h" = xyes; then :
+ EX_CHECK_STATE=YES
+fi
+
+
+
+fi
+
+ else
+ { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING:
+----------------------------------------------------------------------------
+* I found a copy of pkgconfig, but there is no libpng.pc file around.
+ You may want to set the PKG_CONFIG_PATH variable to point to its
+ location.
+----------------------------------------------------------------------------
+ " >&5
+$as_echo "$as_me: WARNING:
+----------------------------------------------------------------------------
+* I found a copy of pkgconfig, but there is no libpng.pc file around.
+ You may want to set the PKG_CONFIG_PATH variable to point to its
+ location.
+----------------------------------------------------------------------------
+ " >&2;}
+ fi
+ fi
+ fi
+
+ if test ${EX_CHECK_STATE} = NO; then
+ { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING:
+----------------------------------------------------------------------------
+* I could not find a working copy of libpng. Check config.log for hints on why
+ this is the case. Maybe you need to set LDFLAGS and CPPFLAGS appropriately
+ so that compiler and the linker can find libpng and its header files. If
+ you have not installed libpng, you can get it either from its original home on
+
+ ftp://ftp.simplesystems.org/pub/libpng/png/src/
+
+ You can find also find an archive copy on
+
+ http://oss.oetiker.ch/rrdtool/pub/libs
+
+ The last tested version of libpng is 1.4.8.
+
+ LIBS=$LIBS
+ LDFLAGS=$LDFLAGS
+ CPPFLAGS=$CPPFLAGS
+
+----------------------------------------------------------------------------
+ " >&5
+$as_echo "$as_me: WARNING:
+----------------------------------------------------------------------------
+* I could not find a working copy of libpng. Check config.log for hints on why
+ this is the case. Maybe you need to set LDFLAGS and CPPFLAGS appropriately
+ so that compiler and the linker can find libpng and its header files. If
+ you have not installed libpng, you can get it either from its original home on
+
+ ftp://ftp.simplesystems.org/pub/libpng/png/src/
+
+ You can find also find an archive copy on
+
+ http://oss.oetiker.ch/rrdtool/pub/libs
+
+ The last tested version of libpng is 1.4.8.
+
+ LIBS=$LIBS
+ LDFLAGS=$LDFLAGS
+ CPPFLAGS=$CPPFLAGS
+
+----------------------------------------------------------------------------
+ " >&2;}
+ EX_CHECK_ALL_ERR=YES
+ LIBS="${ex_check_save_LIBS}"
+ CPPFLAGS="${ex_check_save_CPPFLAGS}"
+ LDFLAGS="${ex_check_save_LDFLAGS}"
+ fi
+ ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+
+
+
ac_ext=c
ac_cpp='$CPP $CPPFLAGS'
ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'