build: finish cross-platform release tooling

scripts/ci_windows_cross.sh

@@ -1,64 +1,26 @@
 #!/usr/bin/env bash
-# CI helper: MinGW-w64 UCRT toolchain via llvm-mingw (no Nix / no /nix).
-# Downloads a pinned release, puts it on PATH, then runs bootstrap_windows.sh.
+# CI helper: Windows x86_64 release with Debian's mingw-w64 UCRT gcc.
+#   apt-get install gcc-mingw-w64-ucrt64 binutils-mingw-w64-ucrt64 nsis   (trixie+)
+# Checks the toolchain, then runs bootstrap_windows.sh, which builds the
+# third-party libs, cst-agent.exe, the zip and the NSIS installer.
 set -euo pipefail
 ROOT="$(cd "$(dirname "$0")/.." && pwd)"
 cd "$ROOT"
 
-VER="${CST_LLVM_MINGW_VER:-20241030}"
-NAME="llvm-mingw-${VER}-ucrt-ubuntu-20.04-x86_64"
-TGZ="/tmp/${NAME}.tar.xz"
-# Prefer /opt when writable (root CI); else unpack under $HOME.
-if [[ -w /opt || "$(id -u)" -eq 0 ]]; then
-  DIR="/opt/${NAME}"
-  PARENT=/opt
-else
-  DIR="${HOME}/${NAME}"
-  PARENT="$HOME"
-fi
-
-if [[ ! -x "$DIR/bin/x86_64-w64-mingw32-gcc" ]]; then
-  echo "==> download $NAME"
-  # Prefer CN-reachable GitHub proxies; raw github.com is often unreachable.
-  urls=(
-    "https://ghfast.top/https://github.com/mstorsjo/llvm-mingw/releases/download/${VER}/${NAME}.tar.xz"
-    "https://ghproxy.net/https://github.com/mstorsjo/llvm-mingw/releases/download/${VER}/${NAME}.tar.xz"
-    "https://gitclone.com/github.com/mstorsjo/llvm-mingw/releases/download/${VER}/${NAME}.tar.xz"
-    "https://github.com/mstorsjo/llvm-mingw/releases/download/${VER}/${NAME}.tar.xz"
-  )
-  ok=0
-  for u in "${urls[@]}"; do
-    echo "  try $u"
-    if curl -fL --retry 2 --connect-timeout 15 --max-time 600 \
-        --retry-delay 2 -o "$TGZ" "$u"; then
-      # Reject tiny error pages that some proxies return with HTTP 200.
-      sz=$(wc -c <"$TGZ")
-      if [[ "$sz" -gt 10000000 ]]; then
-        ok=1
-        break
-      fi
-      echo "  too small ($sz bytes), next mirror"
-    fi
-  done
-  [[ $ok -eq 1 ]] || { echo "failed to download llvm-mingw" >&2; exit 1; }
-  rm -rf "$DIR"
-  mkdir -p "$PARENT"
-  tar -C "$PARENT" -xf "$TGZ"
-fi
-
-export PATH="$DIR/bin:$PATH"
-export MINGW_HOST=x86_64-w64-mingw32
+export MINGW_HOST="${MINGW_HOST:-x86_64-w64-mingw32ucrt}"
 export BUILD_CC="${BUILD_CC:-cc}"
+export CST_REQUIRE_NSIS=1
 
 need() { command -v "$1" >/dev/null || { echo "missing $1" >&2; exit 1; }; }
-need x86_64-w64-mingw32-gcc
-need x86_64-w64-mingw32-windres
-need cmake; need ninja; need perl; need zip; need git; need make
+need "$MINGW_HOST-gcc"
+need "$MINGW_HOST-windres"
+need cmake; need ninja; need perl; need zip; need git; need make; need makensis
 
-if ! printf '#include <stdio.h>\n' | x86_64-w64-mingw32-gcc -dM -E - | grep -qw _UCRT; then
-  echo "toolchain is not UCRT" >&2
+if ! printf '#include <stdio.h>\n' | "$MINGW_HOST-gcc" -dM -E - | grep -qw _UCRT; then
+  echo "$MINGW_HOST-gcc is not UCRT" >&2
   exit 1
 fi
+"$MINGW_HOST-gcc" --version | head -1
 
 # Do not set a global insteadOf: a single broken proxy (e.g. gitclone 502)
 # would take down every third_party clone. build_third_party_mingw.sh tries