initial buildroot for linux 5.15

support/gnuconfig/README.buildroot

@@ -0,0 +1,21 @@
+--- HOWTO ---
+If your package uses config.guess and/or config.sub, then it probably
+relies on the autotools as its build system. In this case, you should
+use the autotools-package infrastructure, which will take care of updating
+the config.guess and/or config.sub files appropriately. See the
+Buildroot documentation for details about the autotools-package
+infrastructure.
+
+If for some reason your package does not use the autotools-package
+infrastructure, you can request the config.guess and/or config.sub
+files of your package to be updated by using:
+
+<pkg>_POST_PATCH_HOOKS += UPDATE_CONFIG_HOOK
+
+--- UPDATE ---
+Run the script 'update' in this directory, and commit the result.
+
+The current Buildroot version is based on this commit of the config.git
+repository (leave alone on its own line, the script updates it):
+
+d7a4dee7cc25e332b990d0a6d9f0ddd42cb33cf5

support/gnuconfig/update

@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+
+set -e
+
+cd "${0%/*}"
+
+git clone https://git.savannah.gnu.org/git/config.git
+sha="$(cd config; git log -1 --pretty=tformat:%H)"
+sed -r -i -e "\$s/.*/${sha}/" README.buildroot
+cp config/config.* .
+for p in $(ls patches/*.patch 2>/dev/null); do
+    patch -p1 < "${p}"
+done
+rm -rf config