Add FLATBUFFERS_COMPATIBILITY string (#5381)

* Add FLATBUFFERS_COMPATIBILITY string

- Add a new __reset method NET/JAVA which hides internal state

* Resolve PR notes

* Use operator new() to __init of Struct and Table

* Restrict visibility of C# Table/Struct to internal level

src/flatc.cpp

@@ -18,10 +18,10 @@
 
 #include <list>
 
-#define FLATC_VERSION "1.11.0"
-
 namespace flatbuffers {
 
+const char *FLATC_VERSION() { return FLATBUFFERS_VERSION(); }
+
 void FlatCompiler::ParseFile(
     flatbuffers::Parser &parser, const std::string &filename,
     const std::string &contents,
@@ -294,7 +294,7 @@ int FlatCompiler::Compile(int argc, const char **argv) {
       } else if (arg == "-M") {
         print_make_rules = true;
       } else if (arg == "--version") {
-        printf("flatc version %s\n", FLATC_VERSION);
+        printf("flatc version %s\n", FLATC_VERSION());
         exit(0);
       } else if (arg == "--grpc") {
         grpc_enabled = true;