Use common licence attributes from lib/licenses.nix

Many (less easily automatically converted) old-style strings
remain.

Where there was any possible ambiguity about the exact version or
variant intended, nothing was changed. IANAL, nor a search robot.

Use `with stdenv.lib` wherever it makes sense.

pkgs/development/libraries/boost-process/default.nix

@@ -24,7 +24,7 @@ stdenv.mkDerivation {
   meta = with stdenv.lib; {
     homepage = "http://www.highscore.de/boost/process0.5/";
     description = "Library to manage system processes";
-    license = "boost-license";
+    license = with licenses; boost;
     platforms = platforms.unix;
     maintainers = with maintainers; [ abbradar ];
   };