Drop the support of VS2013

webcc/globals.h

@@ -2,33 +2,8 @@
 #define WEBCC_GLOBALS_H_
 
 #include <cassert>
+#include <exception>
 #include <string>
-#include <vector>
-
-#include "webcc/version.h"
-
-// -----------------------------------------------------------------------------
-// Macros
-
-// Does the compiler support "= default" for move copy constructor and
-// move assignment operator?
-#ifdef _MSC_VER
-  #if _MSC_VER <= 1800  // VS 2013
-    #define WEBCC_DEFAULT_MOVE_COPY_ASSIGN 0
-  #else
-    #define WEBCC_DEFAULT_MOVE_COPY_ASSIGN 1
-  #endif  // _MSC_VER <= 1800
-#else
-  #define WEBCC_DEFAULT_MOVE_COPY_ASSIGN 1
-#endif  // _MSC_VER
-
-// Explicitly declare the copy constructor and assignment operator as deleted.
-#define WEBCC_DELETE_COPY_ASSIGN(TypeName) \
-  TypeName(const TypeName&) = delete; \
-  TypeName& operator=(const TypeName&) = delete;
-
-// Default user agent.
-#define USER_AGENT "Webcc/" WEBCC_VERSION
 
 namespace webcc {
 
@@ -120,6 +95,9 @@ const char* const kUtf8 = "utf-8";
 
 }  // namespace charsets
 
+// Return default user agent for HTTP headers.
+const std::string& UserAgent();
+
 }  // namespace http
 
 // -----------------------------------------------------------------------------
@@ -156,7 +134,8 @@ public:
   explicit Exception(Error error = kNoError, bool timeout = false,
                      const std::string& details = "");
 
-  const char* what() const override {
+  // Note that `noexcept` is required by GCC.
+  const char* what() const noexcept override {
     return msg_.c_str();
   }