diff --git a/pkgs/development/compilers/llvm/3.9/llvm.nix b/pkgs/development/compilers/llvm/3.9/llvm.nix
index 31677b0ef40..94a8d379fb2 100644
--- a/pkgs/development/compilers/llvm/3.9/llvm.nix
+++ b/pkgs/development/compilers/llvm/3.9/llvm.nix
@@ -134,6 +134,10 @@ in stdenv.mkDerivation rec {
   ] ++ stdenv.lib.optionals (buildPlatform != hostPlatform) [
     "-DCMAKE_CROSSCOMPILING=True"
     "-DLLVM_TABLEGEN=${buildPackages.llvmPackages_39.llvm}/bin/llvm-tblgen"
+  ] ++ stdenv.lib.optionals stdenv.hostPlatform.isMusl [
+    "-DLLVM_HOST_TRIPLE=${stdenv.hostPlatform.config}"
+    "-DLLVM_DEFAULT_TARGET_TRIPLE=${stdenv.targetPlatform.config}"
+    "-DTARGET_TRIPLE=${stdenv.targetPlatform.config}"
   ];
 
   postBuild = ''