Add a script to suppress gdt*Flags.cpp rebuilds for faster builds

tools/suppress-gdt-flags-builds.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+array=(
+    src/KingSystem/GameData/gdtCommonFlags.cpp
+    src/KingSystem/GameData/gdtCommonFlagsUtils.cpp
+    src/KingSystem/GameData/gdtSpecialFlags.cpp
+)
+
+for file in "${array[@]}"
+do
+    echo > $file
+    git update-index --assume-unchanged $file
+done