samples: add Terra samples

source: https://github.com/zdevito/terra/tree/master/tests

samples/Terra/includec.t

@@ -0,0 +1,42 @@
+
+local c = terralib.includec("mytest.h")
+
+terra foo()
+    var a : int = 3
+    return c.myfoobarthing(1,2,3.5,&a) + a
+end
+
+terra bar()
+	return c.myotherthing(4,5)
+end
+
+terra bar2()
+	return c.myfnptr(bar)
+end
+
+terra bar3()
+	var a : c.size_t = 3
+	return a
+end
+
+terra bar4()
+	var opaquething : c.MyStruct2
+	var my = c.MyStruct { 3, 4}
+	return my.a + my.b
+end
+
+terra writefile()
+	c.printf("%f %f %f\n",3.0,4.0,5.0)
+	var f = c.fopen("afile.txt","w")
+	c.fputs("a string\n",f)
+	c.fclose(f)
+end
+
+local test = require("test")
+
+test.eq(foo(),15)
+test.eq(c.myotherthing(1,2),3)
+test.eq(bar2(),9)
+test.eq(bar3(),3)
+test.eq(bar4(),7)
+writefile()