ime_dialog: Initial implementation (#1267)

* Add C string types

* Prepare existing enums

* Added missing enums

* Types update

* State base

* Compile Ime Dialog UI

* UI implementation

* Scoped lock

* Functional implementation

* Link against iconv on macOS

* Fix building on windows

* Better UI

* clang-format

* Some fixes and cleanup

* Enable reserved checks

* clang-format

* Fix default text encoding max size

* clang-format (again)

* Some review changes

* Use std::vector for dynamic strings

* Use CString

* Accept dialog on enter press

* clang-format

* Use ImGUI for encoding/decoding

src/imgui/imgui_config.h

@@ -21,7 +21,6 @@ extern void assert_fail_debug_msg(const char* msg);
         }                                                                                          \
     }())
 
-#define IMGUI_USE_WCHAR32
 #define IMGUI_ENABLE_STB_TRUETYPE
 #define IMGUI_DEFINE_MATH_OPERATORS
 
@@ -30,3 +29,7 @@ extern void assert_fail_debug_msg(const char* msg);
 
 #define IM_VEC4_CLASS_EXTRA                                                                        \
     constexpr ImVec4(float _v) : x(_v), y(_v), z(_v), w(_v) {}
+
+#ifdef IMGUI_USE_WCHAR32
+#error "This project uses 16 bits wchar standard like Orbis"
+#endif