Normalize build scripts and fix Docker Qt dependencies for x86_64

docker-build/build-windows.sh

@@ -1,4 +1,5 @@
 #!/usr/bin/env bash
+export LC_ALL=C
 set -euo pipefail
 
 # Default to not building the installer
@@ -38,6 +39,14 @@ docker run --rm --platform=linux/amd64 \
     set -euo pipefail
     cd /src
 
+    echo '[*] cleaning tree (avoid host-built artifacts)...'
+    [[ -f Makefile ]] && make distclean || true
+    (cd univalue && make distclean) || true
+    rm -rf univalue/.libs univalue/lib/.libs
+    rm -f univalue/config.cache univalue/config.status
+    rm -rf depends/${HOST_TRIPLE}
+    rm -f config.cache
+
     echo '[*] depends (Windows cross, HOST=${HOST_TRIPLE})...'
     cd depends && make HOST=${HOST_TRIPLE} -j\$(nproc) && cd ..
 
@@ -77,4 +86,4 @@ docker run --rm --platform=linux/amd64 \
     echo '[*] build COMPLETED (everything in container) → /out'
   "
 
-echo "[*] Windows executables available in: ${OUT_DIR}"
+echo "[*] Windows executables available in: ${OUT_DIR}"