Conditionally checks std::is_trivially_copyable only if available. (#3327)

include/util/guidance/entry_class.hpp

@@ -4,6 +4,7 @@
 #include <cstddef>
 #include <cstdint>
 #include <functional>
+#include <type_traits>
 
 #include <bitset>
 

include/util/isatty.hpp

@@ -10,7 +10,7 @@
 #define isatty _isatty
 #define fileno _fileno
 #else
-#error Unknown platform - don't know which header to include for isatty()
+#error Unknown platform - isatty implementation required
 #endif // win32
 #endif // unix
 
@@ -29,4 +29,4 @@ inline bool IsStdoutATTY() { return isatty(fileno(stdout)); }
 } // namespace util
 } // namespace osrm
 
-#endif
+#endif