Clarify comment in build script

build.rs

@@ -1,7 +1,7 @@
 // build.rs
 
 fn main() {
-  // Use the linker script.
+  // Tell ld to use linker script.
   println!("cargo::rustc-link-arg=-Tsrc/script.ld");
   // Don't do any magic linker stuff.
   println!("cargo::rustc-link-arg=--omagic");