C++17ification.

C++17ification!

- Filesystem interaction now uses std::filesystem::path.
- Usage of const char*, std::string have been changed to
  std::string_view where appropriate.
- Usage of printf-style functions changed to use fmt.

src/xenia/gpu/gpu_flags.cc

@@ -2,18 +2,18 @@
  ******************************************************************************
  * Xenia : Xbox 360 Emulator Research Project                                 *
  ******************************************************************************
- * Copyright 2013 Ben Vanik. All rights reserved.                             *
+ * Copyright 2020 Ben Vanik. All rights reserved.                             *
  * Released under the BSD license - see LICENSE in the root for more details. *
  ******************************************************************************
  */
 
 #include "xenia/gpu/gpu_flags.h"
 
-DEFINE_string(trace_gpu_prefix, "scratch/gpu/",
-              "Prefix path for GPU trace files.", "GPU");
+DEFINE_path(trace_gpu_prefix, "scratch/gpu/",
+            "Prefix path for GPU trace files.", "GPU");
 DEFINE_bool(trace_gpu_stream, false, "Trace all GPU packets.", "GPU");
 
-DEFINE_string(
+DEFINE_path(
     dump_shaders, "",
     "For shader debugging, path to dump GPU shaders to as they are compiled.",
     "GPU");