make it possible to explicitly disable the legacy TokenList constructors

Author: firewave

simplecpp.h

@@ -57,7 +57,9 @@
 #ifndef SIMPLECPP_TOKENLIST_ALLOW_PTR
 // still provide the legacy API in case we lack the performant wrappers
 #  if !defined(__cpp_lib_string_view) && !defined(__cpp_lib_span)
-#    define SIMPLECPP_TOKENLIST_ALLOW_PTR
+#    define SIMPLECPP_TOKENLIST_ALLOW_PTR 1
+#  else
+#    define SIMPLECPP_TOKENLIST_ALLOW_PTR 0
 #  endif
 #endif
 
@@ -267,7 +269,7 @@ namespace simplecpp {
         TokenList(const unsigned char (&data)[size], std::vector<std::string> &filenames, const std::string &filename=std::string(), OutputList *outputList = nullptr)
             : TokenList(data, size-1, filenames, filename, outputList, 0)
         {}
-#ifdef SIMPLECPP_TOKENLIST_ALLOW_PTR
+#if SIMPLECPP_TOKENLIST_ALLOW_PTR
         /** generates a token list from the given buffer */
         TokenList(const unsigned char* data, std::size_t size, std::vector<std::string> &filenames, const std::string &filename=std::string(), OutputList *outputList = nullptr)
             : TokenList(data, size, filenames, filename, outputList, 0)