package/mesa3d: set cpp_rtti option

This needs to be set based on BR2_PACKAGE_LLVM_RTTI being set.

Fixes:
 - http://autobuild.buildroot.net/results/e2ebc9a73ed421aa6be44fe41bb5224cc12f699d

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit a7f854bce5079608af4cc6c3653b6d71db529cc7)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/mesa3d/mesa3d.mk

@@ -48,6 +48,11 @@ ifeq ($(BR2_PACKAGE_MESA3D_LLVM),y)
 MESA3D_DEPENDENCIES += host-llvm llvm
 MESA3D_MESON_EXTRA_BINARIES += llvm-config='$(STAGING_DIR)/usr/bin/llvm-config'
 MESA3D_CONF_OPTS += -Dllvm=enabled
+ifeq ($(BR2_PACKAGE_LLVM_RTTI),y)
+MESA3D_CONF_OPTS += -Dcpp_rtti=true
+else
+MESA3D_CONF_OPTS += -Dcpp_rtti=false
+endif
 else
 # Avoid automatic search of llvm-config
 MESA3D_CONF_OPTS += -Dllvm=disabled