pstree: refresh sources

Previous first URL was gone ;
+ refactor
+ enhance meta (homepage, license, maintainer)
+ define priority wrt psmisc

pkgs/applications/misc/pstree/default.nix

@@ -1,25 +1,38 @@
 { stdenv, fetchurl }:
 
 stdenv.mkDerivation rec {
-  name = "pstree-2.39";
+  pname = "pstree";
+  version = "2.39";
 
   src = fetchurl {
     urls = [
-      "http://www.sfr-fresh.com/unix/misc/${name}.tar.gz"
-      "https://distfiles.macports.org/pstree/${name}.tar.gz"
+      "https://distfiles.macports.org/${pname}/${pname}-${version}.tar.gz"
+      "https://fossies.org/linux/misc/${pname}-${version}.tar.gz"
+      "ftp://ftp.thp.uni-duisburg.de/pub/source/${pname}-${version}.tar.gz"
     ];
     sha256 = "17s7v15c4gryjpi11y1xq75022nkg4ggzvjlq2dkmyg67ssc76vw";
   };
 
-  unpackPhase = "unpackFile \$src; sourceRoot=.";
+  sourceRoot = ".";
+  buildPhase = ''
+    runHook preBuild
+    $CC $NIX_CFLAGS -o pstree pstree.c
+    runHook postBuild
+  '';
 
-  buildPhase = "pwd; $CC -o pstree pstree.c";
-  installPhase = "mkdir -p \$out/bin; cp pstree \$out/bin";
+  installPhase = ''
+    runHook preInstall
+    install -Dm0555 ${pname} -t $out/bin
+    install -Dm0444 ${pname}.1 -t $out/share/man/man1
+    runHook postInstall
+  '';
 
-  meta = {
+  meta = with stdenv.lib; {
     description = "Show the set of running processes as a tree";
-    license = "GPL";
-    maintainers = [ ];
-    platforms = stdenv.lib.platforms.unix;
+    homepage = "http://www.thp.uni-duisburg.de/pstree/";
+    license = licenses.gpl2;
+    maintainers = [ maintainers.c0bw3b ];
+    platforms = platforms.unix;
+    priority = 5; # Lower than psmisc also providing pstree on Linux platforms
   };
 }