event/ServerSocket: runtime error if abstract sockets are unavailable

src/config/Net.cxx

@@ -29,10 +29,8 @@ ServerSocketAddGeneric(ServerSocket &server_socket, const char *address, unsigne
 		server_socket.AddPort(port);
 	} else if (address[0] == '/' || address[0] == '~') {
 		server_socket.AddPath(ParsePath(address));
-#ifdef __linux__
 	} else if (address[0] == '@') {
 		server_socket.AddAbstract(address);
-#endif
 	} else {
 		server_socket.AddHost(address, port);
 	}

src/event/ServerSocket.cxx

@@ -397,12 +397,14 @@ ServerSocket::AddPath(AllocatedPath &&path)
 }
 
 
-#ifdef __linux__
-
 void
 ServerSocket::AddAbstract(const char *name)
 {
-#if !defined(HAVE_UN)
+#if !defined(__linux__)
+	(void)name;
+
+	throw std::runtime_error("Abstract sockets are only available on Linux");
+#elif !defined(HAVE_UN)
 	(void)name;
 
 	throw std::runtime_error("Local socket support is disabled");
@@ -416,5 +418,3 @@ ServerSocket::AddAbstract(const char *name)
 	AddAddress(std::move(address));
 #endif
 }
-
-#endif

src/event/ServerSocket.hxx

@@ -99,7 +99,6 @@ public:
 	 */
 	void AddPath(AllocatedPath &&path);
 
-#ifdef __linux__
 	/**
 	 * Add a listener on an abstract local socket (Linux specific).
 	 *
@@ -109,7 +108,6 @@ public:
 	 * instead of a null byte
 	 */
 	void AddAbstract(const char *name);
-#endif
 
 	/**
 	 * Add a socket descriptor that is accepting connections.  After this