Correct library info for shmctl to avoid false positives

Author: amai2012

cfg/posix.cfg

@@ -2642,7 +2642,7 @@ The function 'mktemp' is considered to be dangerous due to race conditions and s
       <not-uninit/>
     </arg>
   </function>
-  <!-- http://man7.org/linux/man-pages/man2/shmctl.2.html -->
+  <!-- http://pubs.opengroup.org/onlinepubs/9699919799/functions/shmctl.html -->
   <!-- int shmctl(int shmid, int cmd, struct shmid_ds *buf); -->
   <function name="shmctl">
     <noreturn>false</noreturn>
@@ -2653,11 +2653,8 @@ The function 'mktemp' is considered to be dangerous due to race conditions and s
     <arg nr="2">
       <not-uninit/>
     </arg>
-    <arg nr="3">
-      <not-null/>
-    </arg>
   </function>
-  <!-- http://man7.org/linux/man-pages/man2/shmget.2.html -->
+  <!-- http://pubs.opengroup.org/onlinepubs/009695399/functions/shmget.html -->
   <!-- int shmget(key_t key, size_t size, int shmflg); -->
   <function name="shmget">
     <noreturn>false</noreturn>