fix remaining IPC_64 issue (shmctl)

also cleanup cruft related to the issue

src/ipc/ipc.h

@@ -9,5 +9,3 @@
 #define IPCOP_shmdt     22
 #define IPCOP_shmget    23
 #define IPCOP_shmctl    24
-
-#define IPC_MODERN   0x100

src/ipc/shmctl.c

@@ -5,8 +5,8 @@
 int shmctl(int id, int cmd, struct shmid_ds *buf)
 {
 #ifdef SYS_shmctl
-	return syscall(SYS_shmctl, id, cmd | IPC_MODERN, buf);
+	return syscall(SYS_shmctl, id, cmd | IPC_64, buf);
 #else
-	return syscall(SYS_ipc, IPCOP_shmctl, id, cmd | IPC_MODERN, 0, buf, 0);
+	return syscall(SYS_ipc, IPCOP_shmctl, id, cmd | IPC_64, 0, buf, 0);
 #endif
 }