Red Bear OS — microkernel OS in Rust, based on Redox

Derivative of Redox OS (https://www.redox-os.org) adding:
- AMD GPU driver (amdgpu) via LinuxKPI compat layer
- ext4 filesystem support (ext4d scheme daemon)
- ACPI fixes for AMD bare metal (x2APIC, DMAR, IVRS, MCFG)
- Custom branding (hostname, os-release, boot identity)

Build system is full upstream Redox with RBOS overlay in local/.
Patches for kernel, base, and relibc are symlinked from local/patches/
and protected from make clean/distclean. Custom recipes live in
local/recipes/ with symlinks into the recipes/ search path.

Build:  make all CONFIG_NAME=redbear-full
Sync:   ./local/scripts/sync-upstream.sh

scripts/dual-boot.sh

@@ -0,0 +1,52 @@
+#!/usr/bin/env bash
+
+# This script install Red Bear OS in the free space of your storage device
+# and add a boot entry (if you are using the systemd-boot boot loader)
+
+set -e
+
+if [ -n "$1" ]
+then
+    DISK="$1"
+else
+    DISK=/dev/disk/by-partlabel/RBOS_INSTALL
+fi
+
+if [ ! -b "${DISK}" ]
+then
+    echo "$0: '${DISK}' is not a block device" >&2
+    exit 1
+fi
+
+eval $(make setenv)
+
+IMAGE="${BUILD}/filesystem.img"
+set -x
+rm -f "${IMAGE}"
+make "${IMAGE}"
+sudo popsicle "${IMAGE}" "${DISK}"
+set +x
+
+ESP="$(bootctl --print-esp-path)"
+if [ -z "${ESP}" ]
+then
+    echo "$0: no ESP found" >&2
+    exit 1
+fi
+
+BOOTLOADER="recipes/core/bootloader/target/${ARCH}-unknown-redox/stage/usr/lib/boot/bootloader.efi"
+set -x
+sudo mkdir -pv "${ESP}/EFI" "${ESP}/loader/entries"
+sudo cp -v "${BOOTLOADER}" "${ESP}/EFI/rbos.efi"
+sudo tee "${ESP}/loader/entries/rbos.conf" <<EOF
+title Red Bear OS
+efi /EFI/rbos.efi
+EOF
+set +x
+
+sync
+
+echo "Finished installing Red Bear OS dual boot"
+echo ""
+echo "To mount the RBOS filesystem partition, run:"
+echo "  ./scripts/mount-redoxfs.sh ${DISK}"