llvmPackages_8.libraries.libunwind: add enableShared option

pkgs/development/compilers/llvm/8/libunwind.nix

@@ -1,4 +1,4 @@
-{ stdenv, version, fetch, cmake, fetchpatch }:
+{ stdenv, version, fetch, cmake, fetchpatch, enableShared ? true }:
 
 stdenv.mkDerivation {
   name = "libunwind-${version}";
@@ -19,4 +19,6 @@ stdenv.mkDerivation {
   ];
 
   enableParallelBuilding = true;
+
+  cmakeFlags = stdenv.lib.optional (!enableShared) "-DLIBUNWIND_ENABLE_SHARED=OFF";
 }

pkgs/top-level/static.nix

@@ -154,9 +154,11 @@ in {
         enableShared = false;
         inherit libcxxabi;
       };
+      libunwind = super.llvmPackages_8.libraries.libunwind.override {
+        enableShared = false;
+      };
     };
   };
 
   python27 = super.python27.override { static = true; };
-
 }