fix sigset macro for 64-bit systems (<< was overflowing due to wrong type)
diff --git a/src/internal/pthread_impl.h b/src/internal/pthread_impl.h
index 219bf00..12f8ccf 100644
--- a/src/internal/pthread_impl.h
+++ b/src/internal/pthread_impl.h
@@ -82,7 +82,7 @@
 #define SIGSYSCALL 34
 
 #define SIGPT_SET ((sigset_t *)(unsigned long [1+(sizeof(long)==4)]){ \
-	[sizeof(long)==4] = 3<<(32*(sizeof(long)>4)) })
+	[sizeof(long)==4] = 3UL<<(32*(sizeof(long)>4)) })
 #define SIGTIMER_SET ((sigset_t *)(unsigned long [1+(sizeof(long)==4)]){ \
 	 0x80000000 })