garmin-plugin: switch to fetchFromGitHub, minor formatting, cleanup meta

pkgs/applications/misc/garmin-plugin/default.nix

···
-{ lib, stdenv, fetchurl, garmintools, libgcrypt, libusb-compat-0_1, pkg-config, tinyxml, zlib }:
+{ lib, stdenv, fetchFromGitHub, garmintools, libgcrypt, libusb-compat-0_1, pkg-config, tinyxml, zlib }:
+
 stdenv.mkDerivation rec {
   pname = "garmin-plugin";
   version = "0.3.26";
 
-  src = fetchurl {
-    url = "https://github.com/adiesner/GarminPlugin/archive/V${version}.tar.gz";
-    sha256 = "15gads1fj4sj970m5960dgnhys41ksi4cm53ldkf67wn8dc9i4k0";
+  src = fetchFromGitHub {
+    owner = "adiesner";
+    repo = "GarminPlugin";
+    rev = "V${version}";
+    sha256 = "sha256-l0WAbEsQl1dCADf5gTepYjsA1rQCJMLcrTxRR4PfUus=";
   };
-  sourceRoot = "GarminPlugin-${version}/src";
+
+  preConfigure = ''
+    cd src
+  '';
+
   nativeBuildInputs = [ pkg-config ];
+
   buildInputs = [ garmintools libusb-compat-0_1 libgcrypt tinyxml zlib ];
+
   configureFlags = [
     "--with-libgcrypt-prefix=${libgcrypt.dev}"
     "--with-garmintools-incdir=${garmintools}/include"
     "--with-garmintools-libdir=${garmintools}/lib"
   ];
+
   installPhase = ''
     mkdir -p $out/lib/mozilla/plugins
     cp npGarminPlugin.so $out/lib/mozilla/plugins
   '';
-  meta = {
-    homepage = "http://www.andreas-diesner.de/garminplugin";
-    license = lib.licenses.gpl3;
-    maintainers = [ ];
-    platforms = lib.platforms.linux;
+
+  meta = with lib; {
+    homepage = "https://adiesner.github.io/GarminPlugin/";
+    license = licenses.gpl3Plus;
+    maintainers = with maintainers; [ ];
+    platforms = platforms.linux;
   };
 }