use split_string that returns its result

Author: Daniel Kroening

src/goto-instrument/unwindset.cpp

@@ -23,8 +23,8 @@ void unwindsett::parse_unwind(const std::string &unwind)
 
 void unwindsett::parse_unwindset(const std::string &unwindset)
 {
-  std::vector<std::string> unwindset_loops;
-  split_string(unwindset, ',', unwindset_loops, true, true);
+  std::vector<std::string> unwindset_loops =
+    split_string(unwindset, ',', true, true);
 
   for(auto &val : unwindset_loops)
   {

src/util/config.cpp

@@ -1301,8 +1301,8 @@ void configt::set_classpath(const std::string &cp)
   const char cp_separator = ':';
 #endif
 
-  std::vector<std::string> class_path;
-  split_string(cp, cp_separator, class_path);
+  std::vector<std::string> class_path =
+    split_string(cp, cp_separator);
   java.classpath.insert(
     java.classpath.end(), class_path.begin(), class_path.end());
 }

src/util/unwrap_nested_exception.cpp

@@ -24,8 +24,8 @@ Author: Diffblue Ltd.
 std::string unwrap_exception(const std::exception &e, int level)
 {
   const std::string msg = e.what();
-  std::vector<std::string> lines;
-  split_string(msg, '\n', lines, false, true);
+  std::vector<std::string> lines =
+    split_string(msg, '\n', false, true);
   std::ostringstream message_stream;
   message_stream << std::string(level, ' ') << "exception: ";
   join_strings(