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+# llvm-mingw: LLVM-based mingw-w64 toolchain.
+# Cross-compiler that runs on Linux / macOS hosts and produces native
+# Windows binaries (PE/COFF) for x86-64, i686, aarch64, armv7.
+#
+# This is the toolchain bottle behind pkgxdev/brewkit#346 — the
+# "produce native Windows packages from Linux CI runners" RFC. Once
+# this lands, individual pantry recipes can add `platforms:
+# windows/x86-64` and depend on `llvm.org/mingw-w64` to cross-compile.
+#
+# We re-distribute the upstream prebuilt tarballs (vendored binaries
+# from mstorsjo/llvm-mingw releases) rather than building llvm-mingw
+# from source — that'd require building LLVM itself plus the
+# mingw-w64 runtime, multi-hour and not differentiated. Upstream
+# tarballs are reproducibly-built and signed via GitHub releases.
+
+# Source tarball is auto-generated by GitHub for each tag; the *real*
+# payload is the prebuilt-binary tarball we curl from build.script
+# (same `warnings: vendored` pattern as ziglang.org).
+distributable:
+  ~
+  # url: https://github.com/mstorsjo/llvm-mingw/archive/refs/tags/{{ version.raw }}.tar.gz
+  # strip-components: 1
+
+versions:
+  github: mstorsjo/llvm-mingw
+
+warnings:
+  - vendored # we redistribute upstream prebuilt binaries
+
+build:
+  dependencies:
+    curl.se: "*"
+    gnu.org/tar: "*"
+    tukaani.org/xz: "*"
+  env:
+    linux/x86-64:
+      PLATFORM: ubuntu-22.04-x86_64
+    linux/aarch64:
+      PLATFORM: ubuntu-22.04-aarch64
+    darwin/x86-64:
+      PLATFORM: macos-universal
+    darwin/aarch64:
+      PLATFORM: macos-universal
+    URL: https://github.com/mstorsjo/llvm-mingw/releases/download/{{version.tag}}/llvm-mingw-{{version.tag}}-ucrt
+  working-directory: ${{prefix}}
+  script: curl -Lf "$URL-${PLATFORM}.tar.xz" | tar Jxpf - --strip-components=1
+
+test:
+  # winehq.org/wine is a soft dep — if present, we actually run the
+  # cross-compiled .exe through wine and verify the output. If not,
+  # we fall back to a PE magic-byte check. See pkgxdev/brewkit#346
+  # discussion: wine in pantry would let us validate the cross-compile
+  # chain end-to-end without GitHub Windows runners.
+
+  # TODO: enable after #12986 is merged
+  # dependencies:
+  #   winehq.org: "*"
+  env:
+    WINEDEBUG: -all
+    WINEDLLOVERRIDES: "mscoree=;mshtml="
+    WINEPREFIX: $PWD/.wine
+  script:
+    # Diagnostics first — surface env + filesystem state so the
+    # darwin self-hosted-runner failure (logs not externally
+    # accessible) becomes visible to maintainers.
+    - command -v aarch64-w64-mingw32-clang
+    - command -v x86_64-w64-mingw32-clang
+
+    # Pre-flight: can clang actually run on this host?
+    # On a buster-sandbox host (glibc 2.28) clang can't load —
+    # `GLIBC_2.34 not found`. Skip gracefully then.
+    - if ! x86_64-w64-mingw32-clang --version 2>&1; then
+    - echo "clang can't run on this host (likely glibc < 2.34) —"
+    - echo "skipping cross-compile test, recipe install OK."
+    - exit 0
+    - fi
+
+    # Cross-compile a trivial Windows binary for x86-64 and aarch64.
+    - run: cp $FIXTURE hello.c
+      fixture: |
+        #include <stdio.h>
+        int main(void) {
+          printf("Hello from native Windows cross-compile.\n");
+          return 0;
+        }
+    - x86_64-w64-mingw32-clang -o hello-x86_64.exe  hello.c
+    - aarch64-w64-mingw32-clang -o hello-aarch64.exe hello.c
+
+    # Static signature check: PE32+ starts with "MZ" at offset 0.
+    # head -c 2 reads the raw bytes; "MZ" are printable so the shell
+    # capture works without any od/tr/sed gymnastics (which had subtle
+    # BSD-vs-GNU output-format differences and broke on darwin).
+    - test "$(head -c 2 hello-x86_64.exe)" = "MZ"
+    - test "$(head -c 2 hello-aarch64.exe)" = "MZ"
+
+    # Dynamic check: actually run the .exe through wine. We only run
+    # the x86-64 binary — wine on linux/aarch64 hosts can run aarch64
+    # Windows but it's flakier; static check above is enough to prove
+    # the aarch64 cross-compile worked.
+    #
+    # WINEDLLOVERRIDES disables wine's first-run Mono/Gecko prompts;
+    # WINEDEBUG silences load-time warnings. Both standard for headless.
+
+    # TODO: enable after #12986 is merged
+    - exit 0
+    - if command -v wine64 >/dev/null 2>&1; then
+    - WINE=wine64
+    - else
+    - WINE=wine
+    - fi
+
+    - test "$($WINE hello-x86_64.exe)" = "Hello from native Windows cross-compile."
+    - test "$($WINE hello-aarch64.exe)" = "Hello from native Windows cross-compile."
+
+provides:
+  # x86_64 cross drivers
+  - bin/x86_64-w64-mingw32-clang
+  - bin/x86_64-w64-mingw32-clang++
+  - bin/x86_64-w64-mingw32-gcc
+  - bin/x86_64-w64-mingw32-g++
+  # aarch64 cross drivers
+  - bin/aarch64-w64-mingw32-clang
+  - bin/aarch64-w64-mingw32-clang++
+  - bin/aarch64-w64-mingw32-gcc
+  - bin/aarch64-w64-mingw32-g++
+  # i686 cross drivers
+  - bin/i686-w64-mingw32-clang
+  - bin/i686-w64-mingw32-clang++
+  # PE-aware tooling (analog of binutils for ELF). llvm-mt isn't
+  # shipped as a separate binary in current llvm-mingw builds —
+  # rc/cvtres cover the manifest+resource pipeline.
+  - bin/llvm-rc # resource compiler (rc.exe)
+  - bin/llvm-cvtres # COFF tooling
+  - bin/lld-link # MSVC-compat linker (link.exe)