Fix -Wundef warnings related to __ASSUME_IPC64.  This was addressed
differently upstream:

be481652f272acc117907ac30157cdac46aa1973
Author: Andreas Schwab <schwab@suse.de>
Date:   Tue Aug 18 10:29:30 2015 +0200

    Remove __ASSUME_IPC64

diff --git a/sysdeps/unix/sysv/linux/msgctl.c b/sysdeps/unix/sysv/linux/msgctl.c
index 09d4dc11f779a63f..25f47ce6fdeb19c9 100644
--- a/sysdeps/unix/sysv/linux/msgctl.c
+++ b/sysdeps/unix/sysv/linux/msgctl.c
@@ -65,7 +65,7 @@ compat_symbol (libc, __old_msgctl, msgctl, GLIBC_2_0);
 int
 __new_msgctl (int msqid, int cmd, struct msqid_ds *buf)
 {
-#if __ASSUME_IPC64 > 0
+#ifdef __ASSUME_IPC64
   return INLINE_SYSCALL (ipc, 5, IPCOP_msgctl,
 			 msqid, cmd | __IPC_64, 0, buf);
 #else
diff --git a/sysdeps/unix/sysv/linux/semctl.c b/sysdeps/unix/sysv/linux/semctl.c
index 3a2f1b39cea657e5..f932fb70525a6876 100644
--- a/sysdeps/unix/sysv/linux/semctl.c
+++ b/sysdeps/unix/sysv/linux/semctl.c
@@ -122,7 +122,7 @@ __new_semctl (int semid, int semnum, int cmd, ...)
 
   va_end (ap);
 
-#if __ASSUME_IPC64 > 0
+#ifdef __ASSUME_IPC64
   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
 			 &arg);
 #else
diff --git a/sysdeps/unix/sysv/linux/shmctl.c b/sysdeps/unix/sysv/linux/shmctl.c
index f99ee77f92878b1b..378fda21ea699c73 100644
--- a/sysdeps/unix/sysv/linux/shmctl.c
+++ b/sysdeps/unix/sysv/linux/shmctl.c
@@ -72,7 +72,7 @@ compat_symbol (libc, __old_shmctl, shmctl, GLIBC_2_0);
 int
 __new_shmctl (int shmid, int cmd, struct shmid_ds *buf)
 {
-#if __ASSUME_IPC64 > 0
+#ifdef __ASSUME_IPC64
   return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd | __IPC_64, 0,
 			 buf);
 #else