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

Makefile

@@ -0,0 +1,135 @@
+# This file contains the build system commands configuration
+# and environment variables
+include mk/config.mk
+
+# Build system dependencies
+include mk/depends.mk
+
+all: $(BUILD)/harddrive.img
+
+live:
+	-$(FUMOUNT) $(BUILD)/filesystem/ || true
+	-$(FUMOUNT) /tmp/rbos_installer/ || true
+	rm -f $(BUILD)/rbos-live.iso
+	$(MAKE) $(BUILD)/rbos-live.iso
+
+popsicle: $(BUILD)/rbos-live.iso
+	popsicle-gtk $(BUILD)/rbos-live.iso
+
+image:
+	-$(FUMOUNT) $(BUILD)/filesystem/ || true
+	-$(FUMOUNT) /tmp/rbos_installer/ || true
+	rm -f $(BUILD)/harddrive.img $(BUILD)/rbos-live.iso
+	$(MAKE) all
+
+rebuild:
+	-$(FUMOUNT) $(BUILD)/filesystem/ || true
+	-$(FUMOUNT) /tmp/rbos_installer/ || true
+	rm -rf $(BUILD)/repo.tag $(BUILD)/harddrive.img $(BUILD)/rbos-live.iso
+	$(MAKE) all
+
+# To tell that it's not safe
+# to execute the cookbook binary
+NOT_ON_PODMAN?=0
+
+clean:
+ifeq ($(PODMAN_BUILD),1)
+ifneq ("$(wildcard $(CONTAINER_TAG))","")
+	$(PODMAN_RUN) make $@
+else
+	$(info will not run cookbook clean as container is not built)
+	$(MAKE) clean PODMAN_BUILD=0 NOT_ON_PODMAN=1 SKIP_CHECK_TOOLS=1
+endif # CONTAINER_TAG
+else
+ifneq ($(NOT_ON_PODMAN),1)
+	$(MAKE) repo_clean
+	-$(FUMOUNT) $(BUILD)/filesystem/ || true
+	-$(FUMOUNT) /tmp/rbos_installer/ || true
+endif # NOT_ON_PODMAN
+	rm -rf repo
+	rm -rf $(BUILD) $(PREFIX)
+	$(MAKE) fstools_clean
+endif # PODMAN_BUILD
+
+distclean:
+ifeq ($(PODMAN_BUILD),1)
+ifneq ("$(wildcard $(CONTAINER_TAG))","")
+	$(PODMAN_RUN) make $@
+else
+	$(info will not run cookbook unfetch as container is not built)
+	$(MAKE) distclean PODMAN_BUILD=0 NOT_ON_PODMAN=1 SKIP_CHECK_TOOLS=1
+endif # CONTAINER_TAG
+else
+ifneq ($(NOT_ON_PODMAN),1)
+	$(MAKE) fetch_clean
+endif # NOT_ON_PODMAN
+	$(MAKE) clean NOT_ON_PODMAN=1
+endif # PODMAN_BUILD
+
+pull:
+	git pull
+	rm -f $(FSTOOLS_TAG)
+
+repo: $(BUILD)/repo.tag
+
+repo_clean: c.--all
+
+fetch_clean: u.--all
+
+# Podman build recipes and vars
+include mk/podman.mk
+
+# Disk Imaging and Cookbook tools
+include mk/fstools.mk
+
+# Cross compiler recipes
+include mk/prefix.mk
+
+# Repository maintenance
+include mk/repo.mk
+
+# Disk images
+include mk/disk.mk
+
+# Emulation recipes
+include mk/qemu.mk
+include mk/virtualbox.mk
+
+# CI
+include mk/ci.mk
+
+env: prefix FORCE $(CONTAINER_TAG)
+ifeq ($(PODMAN_BUILD),1)
+	$(PODMAN_RUN) make $@
+else
+	export PATH="$(PREFIX_PATH):$$PATH" && \
+	bash
+endif
+
+setenv: FORCE
+	@echo export ARCH='$(ARCH)'
+	@echo export BOARD='$(BOARD)'
+	@echo export CONFIG_NAME='$(CONFIG_NAME)'
+	@echo BUILD='$(BUILD)'
+
+export RUST_GDB=gdb-multiarch # Necessary when debugging for another architecture than the host
+GDB_KERNEL_FILE=recipes/core/kernel/target/$(TARGET)/build/kernel.sym
+gdb: FORCE
+	rust-gdb $(GDB_KERNEL_FILE) --eval-command="target remote :1234"
+
+# This target allows debugging a userspace application without requiring gdbserver running inside
+# the VM. Because gdb doesn't know when the userspace application is scheduled by the kernel and as
+# it stops the entire VM rather than just the userspace application that the user wants to debug,
+# connecting to a gdbserver running inside the VM is highly encouraged when possible. This target
+# should only be used when the application to debug runs early during boot before the network stack
+# has started or you need to debug the interaction between the application and the kernel.
+# tl;dr: DO NOT USE THIS TARGET UNLESS YOU HAVE TO
+gdb-userspace: FORCE
+	rust-gdb $(GDB_APP_FILE) --eval-command="add-symbol-file $(GDB_KERNEL_FILE)" --eval-command="target remote :1234"
+
+# An empty target
+FORCE:
+
+# Wireshark
+wireshark: FORCE
+	wireshark $(BUILD)/network.pcap