remove some c++98 fallback code

include/libtorrent/entry.hpp

@@ -90,6 +90,7 @@ namespace aux {
 #if (__cplusplus > 201103) || (defined _MSC_VER && _MSC_VER >= 1900)
 		// this enables us to compare a string_view against the std::string that's
 		// held by the std::map
+		// is_transparent was introduced in C++14
 		struct strview_less
 		{
 			using is_transparent = std::true_type;

src/block_cache.cpp

@@ -154,24 +154,12 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #define DEBUG_CACHE 0
 
-#if __cplusplus >= 201103L || defined __clang__
-
 #if DEBUG_CACHE
 #define DLOG(...) std::fprintf(__VA_ARGS__)
 #else
 #define DLOG(...) do {} while (false)
 #endif
 
-#else // cplusplus
-
-#if DEBUG_CACHE
-#define DLOG fprintf
-#else
-#define DLOG TORRENT_WHILE_0 fprintf
-#endif
-
-#endif // cplusplus
-
 namespace libtorrent {
 
 #if DEBUG_CACHE

src/utp_stream.cpp

@@ -119,18 +119,9 @@ void set_utp_stream_logging(bool enable) {
 
 #else
 
-#if __cplusplus >= 201103L || defined __clang__
-
 #define UTP_LOG(...) do {} while(false)
 #define UTP_LOGV(...) do {} while(false)
 
-#else
-
-#define UTP_LOG TORRENT_WHILE_0 printf
-#define UTP_LOGV TORRENT_WHILE_0 printf
-
-#endif // cplusplus
-
 #endif
 
 enum