diff --git a/include/minix/callnr.h b/include/minix/callnr.h
index c38fb14fa..8cfc1fcf0 100644
--- a/include/minix/callnr.h
+++ b/include/minix/callnr.h
@@ -85,9 +85,6 @@
 #define PM_SIG_SET		m2_sigset /* sigset_t */
 #define PM_SIG_CTX		m2_p1	/* struct sigcontext * */
 
-/* Field names for the setgid(2)/setegid(2) calls. */
-#define PM_SETGID_GID		m1_i1	/* gid_t */
-
 /* Field names for the getppid(2) call. */
 #define PM_GETPID_PARENT	m2_i1	/* pid_t */
 
diff --git a/include/minix/ipc.h b/include/minix/ipc.h
index 3789153d4..9906261a1 100644
--- a/include/minix/ipc.h
+++ b/include/minix/ipc.h
@@ -195,6 +195,13 @@ typedef struct {
 } mess_lc_pm_reboot;
 _ASSERT_MSG_SIZE(mess_lc_pm_reboot);
 
+typedef struct {
+	gid_t gid;
+
+	uint8_t padding[52];
+} mess_lc_pm_setgid;
+_ASSERT_MSG_SIZE(mess_lc_pm_setgid);
+
 typedef struct {
 	uid_t uid;
 
@@ -1041,6 +1048,7 @@ typedef struct {
 		mess_lc_pm_priority	m_lc_pm_priority;
 		mess_lc_pm_ptrace	m_lc_pm_ptrace;
 		mess_lc_pm_reboot	m_lc_pm_reboot;
+		mess_lc_pm_setgid	m_lc_pm_setgid;
 		mess_lc_pm_setuid	m_lc_pm_setuid;
 		mess_lc_pm_sysuname	m_lc_pm_sysuname;
 		mess_lc_pm_time		m_lc_pm_time;
diff --git a/lib/libc/sys-minix/setgid.c b/lib/libc/sys-minix/setgid.c
index 269e0cdb6..a34f8c9af 100644
--- a/lib/libc/sys-minix/setgid.c
+++ b/lib/libc/sys-minix/setgid.c
@@ -11,7 +11,7 @@ int setgid(gid_t grp)
   message m;
 
   memset(&m, 0, sizeof(m));
-  m.PM_SETGID_GID = (int) grp;
+  m.m_lc_pm_setgid.gid = grp;
   return(_syscall(PM_PROC_NR, PM_SETGID, &m));
 }
 
@@ -20,6 +20,6 @@ int setegid(gid_t grp)
   message m;
 
   memset(&m, 0, sizeof(m));
-  m.PM_SETGID_GID = (int) grp;
+  m.m_lc_pm_setgid.gid = grp;
   return(_syscall(PM_PROC_NR, PM_SETEGID, &m));
 }
diff --git a/servers/pm/getset.c b/servers/pm/getset.c
index bc4039765..ac4f2f78c 100644
--- a/servers/pm/getset.c
+++ b/servers/pm/getset.c
@@ -123,7 +123,7 @@ int do_set()
 
 	case PM_SETGID:
 	case PM_SETEGID:
-		gid = (gid_t) m_in.PM_SETGID_GID;
+		gid = m_in.m_lc_pm_setgid.gid;
 		if (rmp->mp_realgid != gid && rmp->mp_effuid != SUPER_USER)
 			return(EPERM);
 		if(call_nr == PM_SETGID) rmp->mp_realgid = gid;