Add QNX hellosqrt example source file

The rootfs repo contains the hellosqrt program for QNX that is
dynamically linked against libm. The source file is added here.

examples/src/qnx/hellosqrt.c

@@ -0,0 +1,11 @@
+#include <math.h>
+#include <stdio.h>
+
+int main(int argc, char **argv)
+{
+	double a = atan(1.0);
+	double b = sin(a);
+	double c = 1.0 / b;
+	printf("hello, sqrt(2) = %lf\n", c);
+	return 0;
+}