More MinGW64 fixes

Some more trivial fixes for successfully compiling for Win64.
(cherry picked from commit 7b85371a38)

build_mingw64

@@ -1,4 +1,6 @@
 MINGW=/opt/mingw64
 export PATH=$PATH:$MINGW/bin
+export CFLAGS="-fno-tree-vectorize"
+export CXXFLAGS="$CFLAGS"
 cmake .. -DCMAKE_TOOLCHAIN_FILE=../cmake/modules/Win64Toolchain.cmake -DCMAKE_MODULE_PATH=`pwd`/../cmake/modules/
 

plugins/zynaddsubfx/fltk/src/Fl_Preferences.cxx

@@ -137,7 +137,7 @@ const char *Fl_Preferences::newUUID()
     b[5] = (unsigned char)(r>>8);
     b[6] = (unsigned char)(r>>16);
     b[7] = (unsigned char)(r>>24);
-    unsigned int a = (unsigned int)&t; // four more bytes
+    unsigned int a = (unsigned int)(intptr_t)&t; // four more bytes
     b[8] = (unsigned char)a;
     b[9] = (unsigned char)(a>>8);
     b[10] = (unsigned char)(a>>16);

plugins/zynaddsubfx/fltk/src/fl_ask.cxx

@@ -67,7 +67,7 @@ static char avoidRecursion = 0;
 
 // sets the global return value (ret_val) and closes the window
 static void button_cb(Fl_Widget *bt, void *val) {
-  ret_val = (int)(long)val;
+  ret_val = (int)(intptr_t)val;
   message_form->hide();
 }