skeleton: hack: work with systemd

These symlinks break units with a PrivateTmp=true.

Change-Id: I2f01a07ce6f2075eef3d58cbe63d75e7cda50bd3
diff --git a/configs/czechlight_beaglebone_defconfig b/configs/czechlight_beaglebone_defconfig
index 566dc95..47fb514 100644
--- a/configs/czechlight_beaglebone_defconfig
+++ b/configs/czechlight_beaglebone_defconfig
@@ -8,6 +8,7 @@
 BR2_TARGET_GENERIC_PASSWD_SHA256=y
 BR2_INIT_SYSTEMD=y
 BR2_TARGET_GENERIC_GETTY_PORT="ttyO0"
+BR2_ROOTFS_POST_BUILD_SCRIPT="$(BR2_EXTERNAL_CZECHLIGHT_PATH)/board/czechlight/common/post_build.sh"
 BR2_ROOTFS_POST_IMAGE_SCRIPT="$(BR2_EXTERNAL_CZECHLIGHT_PATH)/board/czechlight/beaglebone/post-image.sh"
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_VERSION=y