fix install with MinGW GCC from command-line

Author: kunzjacq

src/app/CMakeLists.txt

@@ -84,10 +84,10 @@ if (Qt6_FOUND AND WIN32)
   add_custom_command(
     TARGET scantailor
     POST_BUILD
-    COMMAND ${QT_BINDIR}/windeployqt  $<TARGET_FILE_DIR:scantailor>
+    COMMAND ${QT_BINDIR}/windeployqt  $<TARGET_FILE:scantailor>
     COMMENT "deploy qt files alongside binary (e.g. plugins)"
   )
-  install(CODE "execute_process(COMMAND ${QT_BINDIR}/windeployqt ${CMAKE_INSTALL_PREFIX})")
+  install(CODE "execute_process(COMMAND \"${QT_BINDIR}/windeployqt\" \"\$\{CMAKE_INSTALL_PREFIX\}\")")
 endif()
 
 translation_sources(scantailor ${gui_only_sources} ${gui_only_ui_files})