stb: add pkgconfig file

pkgs/development/libraries/stb/default.nix

@@ -1,6 +1,6 @@
-{ lib, stdenv, fetchFromGitHub }:
+{ lib, stdenv, fetchFromGitHub, copyPkgconfigItems, makePkgconfigItem }:
 
-stdenv.mkDerivation {
+stdenv.mkDerivation rec {
   pname = "stb";
   version = "unstable-2021-09-10";
 
@@ -11,11 +11,28 @@ stdenv.mkDerivation {
     sha256 = "0qq35cd747lll4s7bmnxb3pqvyp2hgcr9kyf758fax9lx76iwjhr";
   };
 
+  nativeBuildInputs = [ copyPkgconfigItems ];
+
+  pkgconfigItems = [
+    (makePkgconfigItem rec {
+      name = "stb";
+      version = "1";
+      cflags = [ "-I${variables.includedir}/stb" ];
+      variables = rec {
+        prefix = "${placeholder "out"}";
+        includedir = "${prefix}/include";
+      };
+      inherit (meta) description;
+    })
+  ];
+
   dontBuild = true;
 
   installPhase = ''
+    runHook preInstall
     mkdir -p $out/include/stb
     cp *.h $out/include/stb/
+    runHook postInstall
   '';
 
   meta = with lib; {