Fix special character handling for Windows build： it's may building o…

…n msvc, but need to check.

tiktoken.h

@@ -178,8 +178,11 @@ class tiktoken {
 				}
 
 				if (allowed_special.count(special) == 1) {
-					// return { std::move(special), re2::StringPiece(start, input.begin() - start - special.size()) }; // work fine but faild build msvc
-					return { std::forward<decltype(special)>(special), re2::StringPiece(start, input.begin() - start - special.size()) }; // need to check msvc build./
+					#if ! defined(_WIN32)
+						return { std::move(special), re2::StringPiece(start, input.begin() - start - special.size()) }; // failed on windows building
+					#else
+						return { std::move(special), re2::StringPiece(input.data(), input.begin() - start - special.size()) }; // TODO test msvc use
+					#endif
 				}
 			}