linux-user: Translate pipe2 flags; add to strace

Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NRichard Henderson <rth@twiddle.net>

linux-user/strace.list

@@ -1527,3 +1527,6 @@
 #ifdef TARGET_NR_sync_file_range2
 { TARGET_NR_sync_file_range2, "sync_file_range2", NULL, NULL, NULL },
 #endif
+#ifdef TARGET_NR_pipe2
+{ TARGET_NR_pipe2, "pipe2", NULL, NULL, NULL },
+#endif

linux-user/syscall.c

@@ -5595,7 +5595,8 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
         break;
 #ifdef TARGET_NR_pipe2
     case TARGET_NR_pipe2:
-        ret = do_pipe(cpu_env, arg1, arg2, 1);
+        ret = do_pipe(cpu_env, arg1,
+                      target_to_host_bitmask(arg2, fcntl_flags_tbl), 1);
         break;
 #endif
     case TARGET_NR_times: