package/rrdtool: rrd_graph support needs gcc >= 4.8

Due to the harfbuzz bump to version 2.5.2 gcc >= 4.8 is needed for
rrd_graph support.

Added BR2_TOOLCHAIN_HAS_SYNC_4 dependency to comment.

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/rrdtool/Config.in

@@ -16,6 +16,7 @@ config BR2_PACKAGE_RRDTOOL_RRDGRAPH
 	bool "rrd_graph"
 	default y
 	depends on BR2_TOOLCHAIN_HAS_SYNC_4 # pango -> harfbuzz
+	depends on BR2_TOOLCHAIN_GCC_AT_LEAST_4_8 # pango -> harfbuzz
 	depends on BR2_INSTALL_LIBSTDCPP # freetype support from pango
 	select BR2_PACKAGE_CAIRO
 	select BR2_PACKAGE_CAIRO_PDF
@@ -27,8 +28,10 @@ config BR2_PACKAGE_RRDTOOL_RRDGRAPH
 	  This enables the graphing capabilities ('rrdgraph').
 	  Without this it will only act as a database backend.
 
-comment "rrd_graph support needs a toolchain w/ C++"
-	depends on !BR2_INSTALL_LIBSTDCPP
+comment "rrd_graph support needs a toolchain w/ C++, gcc >= 4.8"
+	depends on !BR2_INSTALL_LIBSTDCPP || \
+		!BR2_TOOLCHAIN_GCC_AT_LEAST_4_8
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4
 
 endif