diff -uNr qemu-2.12.1/linux-user/signal.c qemu-2.12.1.mod/linux-user/signal.c
--- qemu-2.12.1/linux-user/signal.c	2018-08-03 00:48:53.000000000 +0300
+++ qemu-2.12.1.mod/linux-user/signal.c	2018-09-17 16:27:46.990729107 +0300
@@ -206,6 +206,26 @@
     return atomic_xchg(&ts->signal_pending, 1);
 }
 
+#ifdef _NSIG_WORDS
+static int sigorset(sigset_t *dest, const sigset_t *a, const sigset_t *b)
+{
+    int i;
+    if (!dest || !a || !b)
+        return -1;
+    for (i = 0; i < _NSIG_WORDS; i++)
+        dest->sig[i] = a->sig[i] | b->sig[i];
+    return 0;
+}
+#else
+static int sigorset(sigset_t *dest, const sigset_t *a, const sigset_t *b)
+{
+    int i;
+    if (!dest || !a || !b)
+        return -1;
+    *dest = *a | *b;
+    return 0;
+}
+#endif
 /* Wrapper for sigprocmask function
  * Emulates a sigprocmask in a safe way for the guest. Note that set and oldset
  * are host signal set, not guest ones. Returns -TARGET_ERESTARTSYS if
@@ -1418,7 +1438,7 @@
     target_stack_t tuc_stack;
     target_sigset_t tuc_sigmask;
     /* glibc uses a 1024-bit sigset_t */
-    char __unused[1024 / 8 - sizeof(target_sigset_t)];
+    char __qemu_unused[1024 / 8 - sizeof(target_sigset_t)];
     /* last for future expansion */
     struct target_sigcontext tuc_mcontext;
 };
@@ -2004,7 +2024,7 @@
     target_stack_t tuc_stack;
     struct target_sigcontext tuc_mcontext;
     target_sigset_t  tuc_sigmask;	/* mask last for extensibility */
-    char __unused[128 - sizeof(target_sigset_t)];
+    char __qemu_unused[128 - sizeof(target_sigset_t)];
     abi_ulong tuc_regspace[128] __attribute__((__aligned__(8)));
 };