Fix linking with llvm-lib (#1027)

Fix #1026

src/lib.rs

@@ -2472,7 +2472,7 @@ impl Build {
         let target = self.get_target()?;
 
         let (mut cmd, program, any_flags) = self.get_ar()?;
-        if target.contains("msvc") && !program.to_string_lossy().contains("llvm-") {
+        if target.contains("msvc") && !program.to_string_lossy().contains("llvm-ar") {
             // NOTE: -out: here is an I/O flag, and so must be included even if $ARFLAGS/ar_flag is
             // in use. -nologo on the other hand is just a regular flag, and one that we'll skip if
             // the caller has explicitly dictated the flags they want. See