refs #17, defaulting to value_type = wchar_t and string_type = std::wstring on Windows when using fs_std*.hpp helper header

Author: gulrak

include/ghc/fs_std.hpp

@@ -51,6 +51,7 @@ using fstream = std::fstream;
 #endif
 #endif
 #ifndef GHC_USE_STD_FS
+#define GHC_WIN_WSTRING_STRING_TYPE
 #include <ghc/filesystem.hpp>
 namespace fs {
 using namespace ghc::filesystem;

include/ghc/fs_std_fwd.hpp

@@ -54,6 +54,7 @@ using fstream = std::fstream;
 #endif
 #endif
 #ifndef GHC_USE_STD_FS
+#define GHC_WIN_WSTRING_STRING_TYPE
 #define GHC_FILESYSTEM_FWD
 #include <ghc/filesystem.hpp>
 namespace fs {

include/ghc/fs_std_impl.hpp

@@ -45,6 +45,7 @@
 #endif
 #endif
 #ifndef GHC_USE_STD_FS
+#define GHC_WIN_WSTRING_STRING_TYPE
 #define GHC_FILESYSTEM_IMPLEMENTATION
 #include <ghc/filesystem.hpp>
 #endif