Reason: rustc_codegen_llvm attempts to link against the host's llvm without this patch
--- rustc-1.36.0-src/src/librustc_llvm/build.rs
+++ rustc-1.36.0-src/src/librustc_llvm/build.rs
@@ -224,8 +224,8 @@ fn main() {
             println!("cargo:rustc-link-search=native={}", &lib[9..]);
         } else if is_crossed {
             if lib.starts_with("-L") {
-                println!("cargo:rustc-link-search=native={}",
-                         lib[2..].replace(&host, &target));
+                println!("cargo:rustc-link-search=native={}{}",
+                         env::var("XBPS_CROSS_BASE").unwrap(), &lib[2..]);
             }
         } else if lib.starts_with("-l") {
             println!("cargo:rustc-link-lib={}", &lib[2..]);