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/archives/lz4/recipe.toml

@@ -0,0 +1,15 @@
+[source]
+tar = "https://github.com/lz4/lz4/releases/download/v1.10.0/lz4-1.10.0.tar.gz"
+blake3 = "3e69fd475e7852e17594985528b5232afeba7d3d56cfebe2e89071768b2ab36a"
+patches = ["redox.patch"]
+
+[build]
+template = "custom"
+script = """
+DYNAMIC_INIT
+rsync -av --delete "${COOKBOOK_SOURCE}/" ./
+export CPPFLAGS="${CPPFLAGS} -D_REDOX"
+
+${COOKBOOK_MAKE} prefix="/usr"
+${COOKBOOK_MAKE} install DESTDIR="${COOKBOOK_STAGE}" prefix="/usr"
+"""

recipes/archives/lz4/redox.patch

@@ -0,0 +1,34 @@
+diff '--color=auto' -ruwN source/programs/util.h source-new/programs/util.h
+--- source/programs/util.h	2024-07-21 13:29:49.000000000 -0400
++++ source-new/programs/util.h	2024-12-13 02:21:03.032769559 -0500
+@@ -52,6 +52,9 @@
+ #include <time.h>         /* time */
+ #include <limits.h>       /* INT_MAX */
+ #include <errno.h>
++#if defined(_REDOX)
++#  include <sys/time.h>  /* utimes */
++#endif
+ 
+ 
+ 
+@@ -239,12 +242,20 @@
+         timebuf.modtime = statbuf->st_mtime;
+         res += utime(filename, &timebuf);  /* set access and modification times */
+ #else
++        #if defined(_REDOX)
++            struct timeval timebuf[2];
++            memset(timebuf, 0, sizeof(timebuf));
++            timebuf[0].tv_usec = UTIME_NOW;
++            timebuf[1].tv_sec = statbuf->st_mtime;
++            res += utimes(filename, timebuf);
++        #else
+         struct timespec timebuf[2];
+         memset(timebuf, 0, sizeof(timebuf));
+         timebuf[0].tv_nsec = UTIME_NOW;
+         timebuf[1].tv_sec = statbuf->st_mtime;
+         res += utimensat(AT_FDCWD, filename, timebuf, 0);  /* set access and modification times */
+ #endif
++#endif
+     }
+ 
+ #if !defined(_WIN32)

recipes/archives/zstd/01_redox.patch

@@ -0,0 +1,15 @@
+diff -ruwN source/programs/platform.h source-new/programs/platform.h
+--- source/programs/platform.h	2025-02-19 07:04:24.000000000 +0700
++++ source-new/programs/platform.h	2025-07-21 22:52:07.716447723 +0700
+@@ -109,6 +109,11 @@
+ #endif   /* PLATFORM_POSIX_VERSION */
+ 
+ 
++#if defined(__redox__)
++/* TODO: AT_FDCWD && utimensat must be defined to conform _POSIX_VERSION */
++#   define PLATFORM_POSIX_VERSION 1
++#endif
++
+ #if PLATFORM_POSIX_VERSION > 1
+    /* glibc < 2.26 may not expose struct timespec def without this.
+     * See issue #1920. */

recipes/archives/zstd/recipe.toml

@@ -0,0 +1,17 @@
+[source]
+tar = "https://github.com/facebook/zstd/releases/download/v1.5.7/zstd-1.5.7.tar.gz"
+blake3 = "730dca31244abd219e995f03a55d95b2cfb4b3e16cda055a79fa6f30a4f0e1db"
+patches = [
+    "01_redox.patch"
+]
+[build]
+template = "custom"
+script = """
+DYNAMIC_STATIC_INIT
+rsync -av --delete "${COOKBOOK_SOURCE}/" ./
+# TODO: fPIC is the default on linux but not on redox and
+#       required by llvm21 as zstd statically linked there
+export CPPFLAGS="$CPPFLAGS -fPIC"
+${COOKBOOK_MAKE}
+${COOKBOOK_MAKE} install DESTDIR="${COOKBOOK_STAGE}" prefix="/usr"
+"""