SuperBuild: install qwt dll in bin

SuperBuild/patches/QWT/qwt-2-dllinstall-win.diff

+--- QWT-orig/src/src.pro	2018-04-10 18:10:50.950501905 +0200
++++ QWT/src/src.pro	2018-04-10 18:12:56.391144326 +0200
+@@ -25,6 +25,11 @@
+ 
+     CONFIG += dll
+     win32|symbian: DEFINES += QT_DLL QWT_DLL QWT_MAKEDLL
++
++    win32 {
++      dlltarget.path = $${QWT_INSTALL_BIN}
++      INSTALLS += dlltarget
++    }
+ }
+ else {
+     CONFIG += staticlib

SuperBuild/patches/QWT/qwtconfig.pri

@@ -20,6 +20,7 @@ QWT_INSTALL_PREFIX = @SB_INSTALL_PREFIX@
 QWT_INSTALL_DOCS      = $${QWT_INSTALL_PREFIX}/doc
 QWT_INSTALL_HEADERS   = $${QWT_INSTALL_PREFIX}/include
 QWT_INSTALL_LIBS      = $${QWT_INSTALL_PREFIX}/lib
+QWT_INSTALL_BIN       = $${QWT_INSTALL_PREFIX}/bin
 
 ######################################################################
 # Designer plugin