diff --git a/lib/linux-isnptl.c b/lib/linux-isnptl.c
new file mode 100644
index 0000000..d28fe87
--- /dev/null
+++ b/lib/linux-isnptl.c
@@ -0,0 +1,15 @@
+#include <pthread.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+int
+main(void)
+{
+	ulong x;
+
+	x = (ulong)pthread_self();
+	if(x < 1024*1024)
+		exit(1);	/* NOT NPTL */
+	exit(0);
+}