mesa: switch to Local source pointing at local/sources/mesa fork (Phase 2.1, v6.0 2026)

The mesa recipe has been bouncing between direct-edit Wayland
configurations and the legacy Orbital EGL recipe. Each direct
edit kept the source as a git clone of the upstream Redox mesa
(gitlab.redox-os.org/redox-os/mesa, branch redox-24.0, pinned at
0ecd6b66c), with the Redox-targeted EGL/GBM/virgl changes living
in an in-flight Red Bear fork that had no durable address in the
main repo. This is precisely the anti-pattern the
'NO OVERLAY-STYLE PATCHES — SCOPED POLICY' section in
local/AGENTS.md calls out: 'for big external projects (mesa,
wayland, qt, KF6, KWin, SDDM, llvm, libdrm, redox-drm, libepoxy)
the Red Bear fork at local/sources/<component>/ is the durable,
audit-friendly location for these components'.

This commit completes the proper Red Bear full-fork model for
mesa:

  * mainline recipes/libs/mesa/recipe.toml now points at the
    fork via the Local source type:
        [source]
        path = "../../../local/sources/mesa"
    (three levels: recipes/libs/mesa/ -> root -> local/...)
    The cookbook's fetch.rs Local-source branch symlinks
    local/sources/mesa/ into recipes/libs/mesa/source/ at
    fetch time, so the upstream-relative git URL
    'gitlab.redox-os.org/redox-os/mesa' is no longer needed
    here.
  * mainline recipes/libs/mesa/recipe.toml switches to the
    Wayland EGL platform (-Dplatforms=wayland), drops
    liborbital + -lorbital, adds libwayland +
    wayland-protocols + the four wayland-{-client,-server,
    -egl,-drm} link flags. The redox EGL platform
    (src/egl/drivers/dri2/platform_redox.c) is automatically
    excluded from the build by meson under -Dplatforms=wayland;
    the file remains in the source tree as dormant / reference
    code for any future build that re-enables the redox
    platform.
  * mainline recipes/libs/mesa/recipe.toml gets a [package]
    section (version 0.2.3, description anchored on the
    fork's 0.2.3 branch HEAD a7e54995f) so the cookbook's
    package metadata reflects the v6.0 2026 release.
  * recipes/libs/mesa/source is no longer a git submodule
    gitlink (160000) to the upstream Redox mesa. The file
    entry is removed from the index; the cookbook will
    populate the working-tree path from the Local source
    pointer at build time.
  * local/recipes/libs/mesa/recipe.toml is removed. The
    recipe-level fork approach was transitional; the
    durable source is now local/sources/mesa/ (a real
    Red Bear git repo with its own 0.2.3 branch, gitea
    remote, and the upstream redox-24.0 branch left
    intact for clean rebase-onto-upstream). The redundant
    recipe-level fork served no purpose once the mainline
    recipe points at the source-level fork directly.
  * The mesa source-level Redox fixes (Redox EGL/GBM/virgl
    patches + include/sys/ioccom.h stub + removal of 8
    Android-only GitLab CI build patches) are committed on
    the fork's 0.2.3 branch (commits 0ecd6b66c -> a7e54995f,
    130 insertions, 495 deletions across 11 files), not in
    this recipe. The recipe's build target surface
    (EGL/GBM/GLES2/3, swrast/virgl/iris/crocus gallium,
    swrast vulkan, Wayland EGL platform, /scheme/drm/cardN
    via libdrm) is identical to the upstream mesa that the
    fork was baselined on; only the Redox-targeted fixes
    and the cross-compile env glue (sysroot's include/sys/
    ioccom.h) diverge.

A future step (out of scope here) is to follow up the
recipe's [package] description's note about the
include/sys/ioccom.h stub: once relibc exposes the BSD-style
ioctl number macros under <sys/ioctl.h> directly, the
fork's include/sys/ioccom.h and the __redox__ guard in
include/drm-uapi/drm.h should both be removed, and the
fork's 0.2.3 branch should pick up the relibc change as a
forward rebase.

The header comment block of recipes/libs/mesa/recipe.toml
matches the same doc-contract used by
recipes/libs/libdrm/recipe.toml and
recipes/gpu/redox-drm/recipe.toml: where the source lives,
what build target surface the recipe provides, the env
requirements, and the version history. Future contributors
who edit this recipe in isolation will see the full-fork
contract at the top of the file.

local/recipes/libs/mesa/recipe.toml

@@ -1,58 +0,0 @@
-[source]
-git = "https://gitlab.redox-os.org/redox-os/mesa.git"
-upstream = "https://gitlab.freedesktop.org/mesa/mesa"
-branch = "redox-24.0"
-shallow_clone = true
-[build]
-template = "custom"
-dependencies = [
-    "expat",
-    "libdrm",
-    "liborbital",
-    "llvm21",
-    "zlib",
-]
-dev-dependencies = [
-    "llvm21.dev",
-]
-script = """
-DYNAMIC_INIT
-
-#TODO: Should be CPPFLAGS but cookbook_meson isn't reading it
-export CFLAGS+=" -DHAVE_PTHREAD=1 -I${COOKBOOK_SYSROOT}/include/libdrm"
-export LLVM_CONFIG="${TARGET}-llvm-config"
-if [ -x "${HOME}/.redoxer/${TARGET}/toolchain/bin/llvm-config" ]; then
-    export COOKBOOK_HOST_SYSROOT="${HOME}/.redoxer/${TARGET}/toolchain"
-fi
-export LDFLAGS+=" -lorbital"
-
-mkdir -p .cookbook-tools
-ln -sf "$(command -v "${LLVM_CONFIG}")" .cookbook-tools/llvm-config
-export PATH="$(pwd)/.cookbook-tools:${PATH}"
-
-if [ "${COOKBOOK_DYNAMIC}" == "1" ]; then
-    COOKBOOK_MESON_FLAGS+=(-Dshared-llvm=enabled)
-else
-    COOKBOOK_MESON_FLAGS+=(-Dshared-llvm=disabled)
-fi
-
-cookbook_meson \
-    -Ddri-drivers-path=/usr/lib/dri \
-    -Degl=enabled \
-    -Dgbm=enabled \
-    -Dglx=disabled \
-    -Dgallium-drivers=swrast,virgl,iris,crocus \
-    -Dllvm=enabled \
-    -Dosmesa=true \
-    -Dplatforms=redox \
-    -Dshader-cache=disabled \
-    -Dc_args="['-Wno-error=implicit-function-declaration','-Wno-error','-std=gnu11','-Dstatic_assert=_Static_assert']" \
-    -Dcpp_args="['-Wno-error=implicit-function-declaration','-Wno-error']" \
-    -Dvulkan-drivers=swrast \
-    -Dshared-glapi=enabled
-
-# Hack to add LLVM libs, the list can be seen from meson log and check for matches $("${LLVM_CONFIG}" --libs)
-LLVMLIBS="-lLLVMBitReader -lLLVMCore -lLLVMExecutionEngine -lLLVMInstCombine -lLLVMMCDisassembler" 
-LLVMLIBS+=" -lLLVMMCJIT -lLLVMScalarOpts -lLLVMTransformUtils -lLLVMCoroutines -lLLVMLTO"
-sed -i "s/ -lOSMesa / -lOSMesa ${LLVMLIBS} -lstdc++ /" "${COOKBOOK_STAGE}/usr/lib/pkgconfig/osmesa.pc"
-"""