add an example to just test building

examples/just_build.rs

@@ -0,0 +1,22 @@
+#![no_std]
+#![no_main]
+
+#[panic_handler]
+fn panic_handler(info: &core::panic::PanicInfo) -> ! {
+    loop {}
+}
+
+// implementation of tonc's "My first GBA demo"
+// https://coranac.com/tonc/text/first.htm
+
+#[no_mangle]
+pub fn main() -> ! {
+    unsafe {
+        *(0x0400_0000 as *mut u32) = 0x0403;
+        let video = 0x0600_0000 as *mut u16;
+        *video.offset(120 + 80 * 240) = 0x001F;
+        *video.offset(136 + 80 * 240) = 0x001F;
+        *video.offset(120 + 96 * 240) = 0x001F;
+    }
+    loop {}
+}