Error handling only needs last error.

src/error.cpp

@@ -19,15 +19,14 @@
 #include "neocomm.h"
 #include "error.hpp"
 
-#include <vector>
+#include <string>
 
-static std::vector<std::string> errors;
+static std::string last_error;
 
 void add_error(const std::string &error) {
-	if(not errors.empty())
-		errors.push_back(error);
+	last_error = error;
 }
 
 const char *NeoComm_get_last_error() {
-	return errors.back().c_str();
+	return last_error.c_str();
 }