package/mesa3d: add OSMesa classic needs dri swrast

The meson build system now check if dri swrast is enabled
when OSMesa classic is enabled.

See:
https://cgit.freedesktop.org/mesa/mesa/commit/?id=cbbd5bb889a2c271a504c379f36a7cb717a85af4

Signed-off-by: Romain Naour <romain.naour@smile.fr>
Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

Config.in.legacy

@@ -148,7 +148,7 @@ comment "Legacy options removed in 2019.11"
 
 config BR2_PACKAGE_MESA3D_OSMESA
 	bool "mesa OSMesa option renamed"
-	select BR2_PACKAGE_MESA3D_OSMESA_CLASSIC
+	select BR2_PACKAGE_MESA3D_OSMESA_CLASSIC if BR2_PACKAGE_MESA3D_DRI_DRIVER_SWRAST
 	select BR2_LEGACY
 	help
 	  The option was renamed in order to match the naming used

package/mesa3d/Config.in

@@ -267,10 +267,14 @@ comment "Off-screen Rendering"
 
 config BR2_PACKAGE_MESA3D_OSMESA_CLASSIC
 	bool "OSMesa (classic) library"
+	depends on BR2_PACKAGE_MESA3D_DRI_DRIVER_SWRAST
 	help
 	  The OSMesa classic API provides functions for
 	  making off-screen renderings.
 
+comment "OSMesa classic requires dri (classic) swrast"
+	depends on !BR2_PACKAGE_MESA3D_DRI_DRIVER_SWRAST
+
 if BR2_PACKAGE_MESA3D_DRIVER
 
 comment "Additional API Support"