Clear stale Qt configure state for wallet builds

contrib/build-linux-wallet.sh

@@ -24,6 +24,14 @@ require_path() {
   fi
 }
 
+reset_qt_configure_state() {
+  local qt_work="$ROOT/depends/work/build/$HOST/qt"
+  [[ -d "$qt_work" ]] || return 0
+
+  echo "Clearing stale Qt configure state for $HOST..."
+  find "$qt_work" -mindepth 2 -maxdepth 2 -type d -name qtbase-build -prune -exec rm -rf {} +
+}
+
 cd "$ROOT"
 
 require_cmd make
@@ -33,6 +41,8 @@ require_cmd g++
 require_cmd cmake
 require_cmd ninja
 
+reset_qt_configure_state
+
 echo "Building native depends for $HOST..."
 make -C depends HOST="$HOST" NO_QT=0 -j"$JOBS"
 require_path "$BASE_CONFIG"

doc/build-menu.md

@@ -52,7 +52,9 @@ instead of being required as Ubuntu system development packages.
 The Linux Qt wallet option also installs Ubuntu desktop development headers
 needed by Qt's xcb platform plugin, including fontconfig, freetype, xcb, and
 xkbcommon packages. The wallet helper uses the matching `protoc` built by
-`depends/`, so a system protobuf compiler is not required.
+`depends/`, so a system protobuf compiler is not required. It also clears stale
+Qt configure directories before rebuilding, because failed CMake feature checks
+can otherwise be cached between attempts.
 
 Defaults
 --------