Don't use the same llvmdeps.rs for every host.

src/librustc_llvm/lib.rs

@@ -2214,4 +2214,6 @@ pub unsafe fn static_link_hack_this_sucks() {
 // parts of LLVM that rustllvm depends on aren't thrown away by the linker.
 // Works to the above fix for #15460 to ensure LLVM dependencies that
 // are only used by rustllvm don't get stripped by the linker.
-mod llvmdeps;
+mod llvmdeps {
+    include!(env!("CFG_LLVM_LINKAGE_FILE"))
+}