GD support in gnuplot needs PNG support in GD.
So make sure we are getting the full package to enable it, fixes:
http://autobuild.buildroot.net/results/
678bd3babfcb3535e3a9ed1e111f741c3d3101f3/
Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
--without-latex \
--without-cairo
-ifeq ($(BR2_PACKAGE_GD),y)
+ifeq ($(BR2_PACKAGE_GD)$(BR2_PACKAGE_LIBPNG),yy)
GNUPLOT_CONF_OPT += --with-gd
GNUPLOT_DEPENDENCIES += gd
GNUPLOT_CONF_ENV += \