build: finish cross-platform release tooling

scripts/build_third_party_mingw.sh

@@ -106,7 +106,10 @@ build_ncurses() {
   rm -rf "$src/build-mingw"
   mkdir -p "$src/build-mingw"
   cd "$src/build-mingw"
-  ../configure --host="${HOST:-x86_64-w64-mingw32}" --prefix="$PREFIX" \
+  # --host stays canonical (config.sub may not know Debian's "mingw32ucrt");
+  # the tools themselves come from $HOST.
+  CC="${T}gcc" AR="${T}ar" RANLIB="${T}ranlib" STRIP="${T}strip" WINDRES="${T}windres" \
+    ../configure --host=x86_64-w64-mingw32 --prefix="$PREFIX" \
     --without-ada --without-cxx --without-cxx-binding --without-manpages \
     --without-progs --without-tests --without-debug --without-shared \
     --enable-widec --enable-sp-funcs --enable-term-driver \