Update user guide and changelog for local tarball support

Cabal/doc/nix-local-build.rst

@@ -621,9 +621,9 @@ project are:
 
     2. They can specify a glob-style wildcards, which must match one or
        more (a) directories containing a (single) Cabal file, (b) Cabal
-       files (extension ``.cabal``), or (c) [STRIKEOUT:tarballs which
-       contain Cabal packages (extension ``.tar.gz``)] (not implemented
-       yet). For example, to match all Cabal files in all
+       files (extension ``.cabal``), or (c) tarballs which contain Cabal
+       packages (extension ``.tar.gz``).
+       For example, to match all Cabal files in all
        subdirectories, as well as the Cabal projects in the parent
        directories ``foo`` and ``bar``, use
        ``packages: */*.cabal ../{foo,bar}/``

cabal-install/changelog

@@ -19,6 +19,7 @@
 	equivalent to old-style clean, but for nix-style builds.
 	* Ensure that each package selected for a build-depends dependency
 	contains a library (#5304).
+	* Support packages from local tarballs in the cabal.project file.
 
 2.2.0.0 Mikhail Glushenkov <mikhail.glushenkov@gmail.com> March 2018
         * '--with-PROG' and '--PROG-options' are applied to all packages