message: build: Remove duplicated QT_STATICPLUGIN define
  QT_STATICPLUGIN is defined in BITCOIN_QT_CONFIGURE macro.
diff: @@ -246,7 +246,6 @@ dnl Internal. Check if the linked version of Qt was built as static libs.
  dnl Requires: Qt5.
  dnl Requires: INCLUDES and LIBS must be populated as necessary.
  dnl Output: bitcoin_cv_static_qt=yes|no
  -dnl Output: Defines QT_STATICPLUGIN if plugins are static.
  AC_DEFUN([_BITCOIN_QT_IS_STATIC],[
  AC_CACHE_CHECK(for static Qt, bitcoin_cv_static_qt,[
  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
  @@ -263,9 +262,6 @@ AC_DEFUN([_BITCOIN_QT_IS_STATIC],[
  [bitcoin_cv_static_qt=yes],
  [bitcoin_cv_static_qt=no])
  ])
  - if test "x$bitcoin_cv_static_qt" = xyes; then
  - AC_DEFINE(QT_STATICPLUGIN, 1, [Define this symbol for static Qt plugins])
  - fi
  ])
  dnl Internal. Check if the link-requirements for static plugins are met.
  