Set llvm-filecheck binary path into rustc config

Author: GuillaumeGomez

test.sh

@@ -224,6 +224,9 @@ deny-warnings = false
 cargo = "$(which cargo)"
 local-rebuild = true
 rustc = "$HOME/.rustup/toolchains/$rust_toolchain-$TARGET_TRIPLE/bin/rustc"
+
+[target.x86_64-unknown-linux-gnu]
+llvm-filecheck = "`which FileCheck-10`"
 EOF
 
     rustc -V | cut -d' ' -f3 | tr -d '('