diff --git a/configure.ac b/configure.ac
index 0dd4127..420cb71 100644
--- a/configure.ac
+++ b/configure.ac
@@ -212,18 +212,20 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <stdlib.h>],
 			[AC_MSG_RESULT(no)])
 
 AC_MSG_CHECKING(for __attribute__ noreturn)
-AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <stdlib.h>],
-			[ exit(0); } static void foo(void) __attribute__((noreturn));
-			static void foo(void) {exit(0); ])],
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <stdlib.h>
+static void foo(void) __attribute__((noreturn));
+static void foo(void) {exit(0);}],
+			[exit(0);])],
 			[AC_MSG_RESULT(yes)
 			AC_DEFINE(HAVE___ATTRIBUTE__NORETURN, 1, [Define if your compiler has __attribute__ noreturn])],
 			[AC_MSG_RESULT(no)])
 
 AC_MSG_CHECKING(for __attribute__ format)
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <stdlib.h>
-				#include <stdarg.h>],
-			[ exit(0); } static int foo(char *fmt, ...) __attribute__((format (printf, 1, 2)));
-			static int foo(char *fmt, ...) { ])],
+				#include <stdarg.h>
+static void foo(char *fmt, ...) __attribute__((format (printf, 1, 2)));
+static void foo(char *fmt, ...) {}],
+			[exit(0);])],
 			[AC_MSG_RESULT(yes)
 			AC_DEFINE(HAVE___ATTRIBUTE__FORMAT, 1, [Define if your compiler has __attribute__ format])],
 			[AC_MSG_RESULT(no)])
diff --git a/doc/book/src/guides/using-oidentd-with-quassel.md b/doc/book/src/guides/using-oidentd-with-quassel.md
index d5bdbcf..03d12c8 100644
--- a/doc/book/src/guides/using-oidentd-with-quassel.md
+++ b/doc/book/src/guides/using-oidentd-with-quassel.md
@@ -79,7 +79,7 @@ file:
 chmod 0711 ~quasselcore
 ```
 
-Finally, make sure Quassel is run with the `--oidentd` flag.
+Finally, make sure Quassel is run with the `--oidentd` flag. To modify the systemd unit file of Quassel, run `sudo systemctl edit --full quasselcore` and append the flag to the `ExecStart` line.
 
 Your changes will take effect after you reload oidentd and restart Quassel.
 
diff --git a/src/netlink.h b/src/netlink.h
index 57366fe..8565ce5 100644
--- a/src/netlink.h
+++ b/src/netlink.h
@@ -18,14 +18,6 @@
 #define NETLINK_TCPDIAG	4
 #define TCPDIAG_GETSOCK	18
 
-#define NLMSG_ERROR		0x2
-#define NLMSG_DONE		0x3
-
-#define NLMSG_SPACE(len) NLMSG_ALIGN(NLMSG_LENGTH(len))
-#define NLMSG_DATA(nlh)  ((void*)(((char*)nlh) + NLMSG_LENGTH(0)))
-#define NLMSG_NEXT(nlh,len) ((len) -= NLMSG_ALIGN((nlh)->nlmsg_len), \
-	(struct nlmsghdr*)(((char*)(nlh)) + NLMSG_ALIGN((nlh)->nlmsg_len)))
-
 /* Socket identity */
 struct tcpdiag_sockid {
 	u_int16_t tcpdiag_sport;