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

recipes/dev/patch/03_renameat2.patch

@@ -0,0 +1,15 @@
+--- source-old/lib/renameat2.c	2018-02-03 05:41:53.000000000 -0700
++++ source/lib/renameat2.c	2025-11-01 08:39:54.945513820 -0600
+@@ -70,6 +70,7 @@
+    Obey FLAGS when doing the renaming.  If FLAGS is zero, this
+    function is equivalent to renameat (FD1, SRC, FD2, DST).  */
+ 
++#if !defined(__redox__)
+ int
+ renameat2 (int fd1, char const *src, int fd2, char const *dst,
+            unsigned int flags)
+@@ -225,3 +226,4 @@
+ 
+ #endif /* !HAVE_RENAMEAT */
+ }
++#endif