Build: Add configure defines to detailed version output

src/rev.cpp.in

@@ -53,6 +53,11 @@ const char _openttd_build_date[] = __DATE__ " " __TIME__;
  */
 const char _openttd_build_configure[] = "!!CONFIGURE_INVOCATION!!";
 
+/**
+ * The configure defines used to build OpenTTD
+ */
+const char _openttd_build_configure_defines[] = "!!CONFIGURE_DEFINES!!";
+
 /**
  * The git revision hash of this version.
  */