diff --git a/include/signal.h b/include/signal.h
index 121d3027..877b2d55 100644
--- a/include/signal.h
+++ b/include/signal.h
@@ -25,8 +25,13 @@
 #include_next <signal.h>
 #else //! SYSTEM_LIBC
 
+#define _NSIG 64
 
-typedef long sigset_t;
+#define _SIGSET_NITEMS (_NSIG / (8 * sizeof(unsigned long)))
+
+typedef struct {
+  unsigned long items[_SIGSET_NITEMS];
+} sigset_t;
 typedef long stack_t;
 
 #include <sys/types.h>
diff --git a/lib/linux/signal.c b/lib/linux/signal.c
index 19f09d64..6d95b6ab 100644
--- a/lib/linux/signal.c
+++ b/lib/linux/signal.c
@@ -41,12 +41,16 @@ signal (int signum, sighandler_t action)
 #if __i386__
   return _sys_call2 (SYS_signal, signum, action);
 #else
-  static struct sigaction setup_action = { -1 };
+  static struct sigaction setup_action = { 0 };
   static struct sigaction old = { 0 };
+  unsigned short bitindex;
+  unsigned short itembitcount;
 
   setup_action.sa_handler = action;
   setup_action.sa_restorer = _restorer;
-  setup_action.sa_mask = __sigmask (signum);
+  bitindex = signum - 1;
+  itembitcount = 8 * sizeof(setup_action.sa_mask.items[0]);
+  setup_action.sa_mask.items[bitindex / itembitcount] = 1 << (bitindex % itembitcount);
   old.sa_handler = SIG_DFL;
   setup_action.sa_flags = SA_RESTORER | SA_RESTART;
   int r = _sys_call4 (SYS_rt_sigaction, signum, &setup_action, &old, sizeof (sigset_t));