fix binary size

Author: nobonobo

builder/sizes_test.go

@@ -42,9 +42,9 @@ func TestBinarySize(t *testing.T) {
 	// This is a small number of very diverse targets that we want to test.
 	tests := []sizeTest{
 		// microcontrollers
-		{"hifive1b", "examples/echo", 4277, 307, 0, 2260},
-		{"microbit", "examples/serial", 2836, 368, 8, 2256},
-		{"wioterminal", "examples/pininterrupt", 8095, 1661, 132, 7488},
+		{"hifive1b", "examples/echo", 4313, 323, 0, 2260},
+		{"microbit", "examples/serial", 2838, 382, 8, 2256},
+		{"wioterminal", "examples/pininterrupt", 8109, 1663, 132, 7488},
 
 		// TODO: also check wasm. Right now this is difficult, because
 		// wasm binaries are run through wasm-opt and therefore the