Adds pkg-config file and headers (#17173)

pkgs/development/libraries/libui/default.nix

@@ -1,25 +1,38 @@
 { stdenv, fetchgit, cmake, pkgconfig, gtk3 }:
 
-stdenv.mkDerivation rec {
-  version = "3.1.a";
-  name = "libui-${version}";
-  src  = fetchgit {
-    url    = "https://github.com/andlabs/libui.git";
-    rev    = "6ebdc96b93273c3cedf81159e7843025caa83058";
-    sha256 = "1lpbfa298c61aarlzgp7vghrmxg1274pzxh1j9isv8x758gk6mfn";
-  };
+let
+  shortName = "libui";
+  version   = "3.1a";
+in
+  stdenv.mkDerivation rec {
+    name = "${shortName}-${version}";
+    src  = fetchgit {
+      url    = "https://github.com/andlabs/libui.git";
+      rev    = "6ebdc96b93273c3cedf81159e7843025caa83058";
+      sha256 = "1lpbfa298c61aarlzgp7vghrmxg1274pzxh1j9isv8x758gk6mfn";
+    };
 
-  buildInputs = [ cmake pkgconfig gtk3 ];
+    buildInputs = [ cmake pkgconfig gtk3 ];
 
-  installPhase = ''
-    mkdir -p $out
-    mv ./out/libui.so.0 $out/libui.so.0
-  '';
+    installPhase = ''
+      mkdir -p $out/{include,lib}
+      mkdir -p $out/lib/pkgconfig
 
-  meta = with stdenv.lib; {
-    description = "Simple and portable (but not inflexible) GUI library in C that uses the native GUI technologies of each platform it supports.";
-    homepage    = https://github.com/andlabs/libui;
-    platforms   = platforms.linux;
-    license     = licenses.mit;
-  };
-}
+      mv ./out/${shortName}.so.0 $out/lib/
+      ln -s $out/lib/${shortName}.so.0 $out/lib/${shortName}.so
+
+      cp $src/ui.h $out/include
+      cp $src/ui_unix.h $out/include
+
+      cp ${./libui.pc} $out/lib/pkgconfig/${shortName}.pc
+      substituteInPlace $out/lib/pkgconfig/${shortName}.pc \
+        --subst-var-by out $out \
+        --subst-var-by version "${version}"
+    '';
+
+    meta = {
+      homepage    = https://github.com/andlabs/libui;
+      description = "Simple and portable (but not inflexible) GUI library in C that uses the native GUI technologies of each platform it supports.";
+      platforms   = stdenv.lib.platforms.linux;
+    };
+  }

pkgs/development/libraries/libui/libui.pc

@@ -0,0 +1,11 @@
+prefix=@out@
+exec_prefix=${prefix}
+libdir=${exec_prefix}/lib
+includedir=${exec_prefix}/include
+
+Name: libui
+Description: Simple and portable (but not inflexible) GUI library
+Version: @version@
+
+Libs: -L${libdir} -lui
+Cflags: -I${includedir}