Add `reflect.struct_field_count` that returns the number of fields in a struct type

Example:
```odin
package struct_count_example

import "core:fmt"
import "core:reflect"
import "core:dynlib"

Foo :: struct{
	one: int,
	two: f32,
}

Bar :: struct {
	three: int,
	four:  bool,
	five:  f64,
}

Game_Api :: struct {
	init:      proc(api: ^Game_Api),
	update:    proc(api: ^Game_Api),

	using foo: Foo,
	bar:       Bar,

	// Private stuff
	reload_count: int,
	__handle:     rawptr,
}
API_PRIVATE_COUNT :: 2

game_api: Game_Api

main :: proc() {
	fmt.printfln("Game_Api, .Top:       %v", reflect.struct_field_count(Game_Api))              // 6
	fmt.printfln("Game_Api, .Using:     %v", reflect.struct_field_count(Game_Api, .Using))      // 8
	fmt.printfln("Game_Api, .Recursive: %v", reflect.struct_field_count(Game_Api, .Recursive))  // 11

	symbols_loaded, _  := dynlib.initialize_symbols(&game_api, "game.dll")
	symbols_expected   := reflect.struct_field_count(Game_Api) - API_PRIVATE_COUNT

	if symbols_loaded == -1 {
		fmt.eprintln("Couldn't load game.dll")
		return
	} else if symbols_loaded != symbols_expected {
		fmt.eprintfln("Expected %v symbols, got %v", symbols_expected, symbols_loaded)
		return
	}
}
```

0 files changed, 0 insertions, 0 deletions