Replace absolute paths with relative ones

Modern compilers allow reaching external crates
like std or core via relative paths in modules
outside of lib.rs and main.rs.

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -122,7 +122,7 @@ unsafe fn configure_llvm(sess: &Session) {
 
     llvm::LLVMInitializePasses();
 
-    ::rustc_llvm::initialize_available_targets();
+    rustc_llvm::initialize_available_targets();
 
     llvm::LLVMRustSetLLVMOptions(llvm_args.len() as c_int, llvm_args.as_ptr());
 }