pkgStatic.dash: fix build

`libedit` declares a dependency on `libncurses`, but since dash doesn't use pkg-config it doesn't register the transitive dependencies.

pkgs/shells/dash/default.nix

@@ -2,6 +2,7 @@
 , stdenv
 , buildPackages
 , autoreconfHook
+, pkg-config
 , fetchurl
 , fetchpatch
 , libedit
@@ -37,12 +38,16 @@ stdenv.mkDerivation rec {
 
   strictDeps = true;
   # configure.ac patched; remove on next release
-  nativeBuildInputs = [ autoreconfHook ];
+  nativeBuildInputs = [ autoreconfHook ]
+    ++ lib.optionals stdenv.hostPlatform.isStatic [ pkg-config ];
 
   depsBuildBuild = [ buildPackages.stdenv.cc ];
   buildInputs = [ libedit ];
 
   configureFlags = [ "--with-libedit" ];
+  preConfigure = lib.optional stdenv.hostPlatform.isStatic ''
+    export LIBS="$(pkg-config --libs --static libedit)"
+  '';
 
   enableParallelBuilding = true;