frawk: fix build on darwin

pkgs/tools/text/frawk/default.nix

@@ -6,6 +6,7 @@
 , zlib
 , features ? [ "default" ]
 , llvmPackages_12
+, stdenv
 }:
 
 rustPlatform.buildRustPackage rec {
@@ -30,6 +31,11 @@ rustPlatform.buildRustPackage rec {
     export RUSTC_BOOTSTRAP=1
   '';
 
+  # Work around https://github.com/NixOS/nixpkgs/issues/166205.
+  env = lib.optionalAttrs stdenv.cc.isClang {
+    NIX_LDFLAGS = "-l${stdenv.cc.libcxx.cxxabi.libName}";
+  };
+
   # depends on cpu instructions that may not be available on builders
   doCheck = false;