Replace GCC-specific attribute with [[nodiscard]] attribute (#6899)

include/util/alias.hpp

@@ -28,9 +28,9 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef OSRM_UTIL_ALIAS_HPP
 #define OSRM_UTIL_ALIAS_HPP
 
-#include <boost/numeric/conversion/cast.hpp>
+#include <cstddef>
 #include <functional>
-#include <iostream>
+#include <ostream>
 #include <type_traits>
 
 namespace osrm

include/util/attributes.hpp

@@ -1,13 +0,0 @@
-#ifndef OSRM_ATTRIBUTES_HPP_
-#define OSRM_ATTRIBUTES_HPP_
-
-// OSRM_ATTR_WARN_UNUSED - caller has to use function's return value
-// https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html
-
-#if defined(__GNUC__) && (__GNUC__ >= 4)
-#define OSRM_ATTR_WARN_UNUSED __attribute__((warn_unused_result))
-#else
-#define OSRM_ATTR_WARN_UNUSED
-#endif
-
-#endif

include/util/guidance/name_announcements.hpp

@@ -6,18 +6,16 @@
 #include "extractor/name_table.hpp"
 #include "extractor/suffix_table.hpp"
 
-#include "util/attributes.hpp"
 #include "util/typedefs.hpp"
 
+#include <boost/algorithm/string.hpp>
+
 #include <algorithm>
 #include <string>
 #include <tuple>
 #include <utility>
 #include <vector>
 
-#include <boost/algorithm/string.hpp>
-#include <boost/algorithm/string/predicate.hpp>
-
 namespace osrm::util::guidance
 {
 // Name Change Logic