libdrm: migrate to Red Bear fork; apply redox patches in-tree

Migrate the libdrm recipe from the tar+patches shape (redox.patch + four
P1-P4 patches from local/patches/libdrm/) to a Local source pointing at
the new Red Bear fork at local/sources/libdrm/. The fork is based on
upstream libdrm 2.4.125 (https://gitlab.freedesktop.org/mesa/libdrm) and
already has the full redox.patch series applied in-tree.

The P1-P4 patch files referenced from the previous recipe
(P1-drm-ioctl-bridge, P2-drm-get-pci-info, P3-drm-get-version-driver-name,
P4-drmGetDeviceFromDevId-redox) were already merged into redox.patch and
no longer existed in local/patches/. Consolidating everything into a
single in-tree fork is the durable form per the FULL FORK PRINCIPLE.

The fork's redox divergence covers:
  - include/drm/drm.h: include <sys/ioctl.h> on __redox__ instead of
    <sys/ioccom.h>
  - xf86drm.h: Redox-aware ioctl type definitions
  - xf86drm.c: major()/minor()/makedev() macros from musl for __redox__,
    open_memstream fallback path (returns NULL with diagnostic on
    __redox__), redox_drm_write_all helper, and the drmOpen /
    drmGetDeviceFromDevId / etc. rewrites that dispatch through scheme:
    paths on Redox
  - xf86drmMode.c: Redox shim for drmModeGetResources /
    drmModeGetConnector / etc. and the mode probing path
  - xf86drm_redox.h: new header providing the Redox-side helper API
    (open scheme:, drm fd adaptation, dev_t packing) used by xf86drm.c

Recipe changes:
  - source: tar + patches list -> Local { path = '../../../../local/sources/libdrm' }
    (the recipe lives under both recipes/wip/x11/libdrm and
    recipes/libs/libdrm symlinks into local/recipes/libs/libdrm; the
    four-.. path resolves correctly from both locations to
    local/sources/libdrm).
  - version: bumped to 0.2.3 (Red Bear fork tracking upstream 2.4.125).
  - description: marked v6.0 2026 Red Bear fork.
  - removed: redox.patch and source/ / source.tar / target/ artifacts
    under the recipe directory; they are no longer referenced and the
    fork is the single source of truth.

Verified: ./target/release/repo cook libdrm (with
REDBEAR_ALLOW_PROTECTED_FETCH=1) builds successfully and publishes
libdrm 0.2.3 to repo/x86_64-unknown-redox/ with the fork's commit
identifier pinned.

local/recipes/libs/libdrm/recipe.toml

@@ -1,7 +1,31 @@
+# libdrm — DRM/KMS user-space library for Red Bear OS.
+#
+# This recipe builds the Red Bear libdrm fork maintained at
+# local/sources/libdrm/. The fork is based on upstream libdrm 2.4.125
+# (https://gitlab.freedesktop.org/mesa/libdrm) with the redox.patch
+# series applied in-tree. The fork adds the Redox-side ioctl/ioctl-com
+# and scheme: dispatch path needed by redox-drm and Mesa radeonsi/iris.
+#
+# On Redox, libdrm talks to:
+#   * redox-drm                (local/recipes/gpu/redox-drm)
+#   * scheme: memory, scheme:irq, scheme:pci
+#   * relibc (for the open_memstream fallback and major/minor shims)
+#
+# The previous P1-P4 patch series referenced by the recipe
+# (P1-drm-ioctl-bridge, P2-drm-get-pci-info, P3-drm-get-version-driver-name,
+# P4-drmGetDeviceFromDevId-redox) is now folded into the single
+# redox.patch that ships inside the source fork. No external patch
+# files are needed; the build is fully offline and reproducible from
+# the fork's git HEAD.
+#
+# Build target: amdgpu=enabled. intel/nouveau/radeon/vmwgfx are
+# disabled by default because the Redox GPU driver surface is
+# brought up through redox-drm and we only need the AMD backend for
+# the redbear-full target's radeonsi Mesa path. Tests are disabled
+# because the cross-compiled test binaries cannot run in the
+# cookbook build environment.
 [source]
-tar = "https://gitlab.freedesktop.org/mesa/libdrm/-/archive/libdrm-2.4.125/libdrm-libdrm-2.4.125.tar.gz"
-blake3 = "33e6448252639f4ff8a8cd30129b335c5d85356c1c93f8d77a79221003b14f66"
-patches = ["redox.patch", "../../../local/patches/libdrm/P1-drm-ioctl-bridge.patch", "../../../local/patches/libdrm/P2-drm-get-pci-info.patch", "../../../local/patches/libdrm/P3-drm-get-version-driver-name.patch", "../../../local/patches/libdrm/P4-drmGetDeviceFromDevId-redox.patch"]
+path = "../../../../local/sources/libdrm"
 
 [build]
 template = "meson"
@@ -14,3 +38,7 @@ mesonflags = [
     "-Dtests=false",
     "-Dc_args=-Wno-unused-function",
 ]
+
+[package]
+version = "0.2.3"
+description = "libdrm 0.2.3 (v6.0 2026) — DRM/KMS user-space library, Red Bear fork. Provides libdrm.so.2, the amdgpu helpers, the xf86drm device-open helpers, the mode-setting API, and the open_memstream/major/minor portability shims required to build Mesa radeonsi and the redox-drm scheme against the Redox target. Forked from upstream libdrm 2.4.125 (gitlab.freedesktop.org/mesa/libdrm); the redox.patch series is applied in-tree at local/sources/libdrm/."