Bump buildroot to 2020.11-rc1 (#985)

* Update buildroot-patches for 2020.11-rc1 buildroot

* Update buildroot to 2020.11-rc1

Signed-off-by: Stefan Agner <stefan@agner.ch>

* Don't rely on sfdisk --list-free output

The --list-free (-F) argument does not allow machine readable mode. And
it seems that the output format changes over time (different spacing,
using size postfixes instead of raw blocks).

Use sfdisk json output and calculate free partition space ourselfs. This
works for 2.35 and 2.36 and is more robust since we rely on output which
is meant for scripts to parse.

* Migrate defconfigs for Buildroot 2020.11-rc1

In particular, rename BR2_TARGET_UBOOT_BOOT_SCRIPT(_SOURCE) to
BR2_PACKAGE_HOST_UBOOT_TOOLS_BOOT_SCRIPT(_SOURCE).

* Rebase/remove systemd patches for systemd 246

* Drop apparmor/libapparmor from buildroot-external

* hassos-persists: use /run as directory for lockfiles

The U-Boot tools use /var/lock by default which is not created any more
by systemd by default (it is under tmpfiles legacy.conf, which we no
longer install).

* Disable systemd-update-done.service

The service is not suited for pure read-only systems. In particular the
service needs to be able to write a file in /etc and /var. Remove the
service. Note: This is a static service and cannot be removed using
systemd-preset.

* Disable apparmor.service for now

The service loads all default profiles. Some might actually cause
problems. E.g. the profile for ping seems not to match our setup for
/etc/resolv.conf:
[85503.634653] audit: type=1400 audit(1605286002.684:236): apparmor="DENIED" operation="open" profile="ping" name="/run/resolv.conf" pid=27585 comm="ping" requested_mask="r" denied_mask="r" fsuid=0 ouid=0

buildroot/package/linux-headers/Config.in.host

@@ -6,7 +6,7 @@ config BR2_PACKAGE_HOST_LINUX_HEADERS
 choice
 	prompt "Kernel Headers"
 	default BR2_KERNEL_HEADERS_AS_KERNEL if BR2_LINUX_KERNEL
-	default BR2_KERNEL_HEADERS_5_4
+	default BR2_KERNEL_HEADERS_5_9
 	help
 	  Select the kernel version to get headers from.
 
@@ -53,6 +53,14 @@ config BR2_KERNEL_HEADERS_4_19
 config BR2_KERNEL_HEADERS_5_4
 	bool "Linux 5.4.x kernel headers"
 	select BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_4
+
+config BR2_KERNEL_HEADERS_5_8
+	bool "Linux 5.8.x kernel headers"
+	select BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_8
+
+config BR2_KERNEL_HEADERS_5_9
+	bool "Linux 5.9.x kernel headers"
+	select BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_9
 	select BR2_KERNEL_HEADERS_LATEST
 
 config BR2_KERNEL_HEADERS_VERSION
@@ -127,8 +135,28 @@ choice
 	  If your kernel headers are more recent than the latest version
 	  in the choice, then select the latest version.
 
+config BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_5_9
+	bool "5.9.x or later"
+	select BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_9
+
+config BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_5_8
+	bool "5.8.x"
+	select BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_8
+
+config BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_5_7
+	bool "5.7.x"
+	select BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_7
+
+config BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_5_6
+	bool "5.6.x"
+	select BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_6
+
+config BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_5_5
+	bool "5.5.x"
+	select BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_5
+
 config BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_5_4
-	bool "5.4.x or later"
+	bool "5.4.x"
 	select BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_4
 
 config BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_5_3
@@ -323,6 +351,8 @@ config BR2_DEFAULT_KERNEL_HEADERS
 	default "4.14.200"	if BR2_KERNEL_HEADERS_4_14
 	default "4.19.150"	if BR2_KERNEL_HEADERS_4_19
 	default "5.4.70"	if BR2_KERNEL_HEADERS_5_4
+	default "5.8.14"	if BR2_KERNEL_HEADERS_5_8
+	default "5.9"		if BR2_KERNEL_HEADERS_5_9
 	default BR2_DEFAULT_KERNEL_VERSION if BR2_KERNEL_HEADERS_VERSION
 	default "custom"	if BR2_KERNEL_HEADERS_CUSTOM_TARBALL
 	default BR2_KERNEL_HEADERS_CUSTOM_REPO_VERSION \