gnu: go-github-com-mattn-go-pointer: Move to golang-xyz.

* gnu/packages/golang.scm (go-github-com-mattn-go-pointer): Move from
here ...
* gnu/packages/golang-xyz.scm: ... to here.

Change-Id: Iba5e71a870bbbce1dfea80ceafcd66e56883887b

gnu/packages/golang.scm

@@ -4351,31 +4351,6 @@ The yaml package supports most of YAML 1.2, but preserves some behavior from
     (description "This package provides a Golang Matrix client.")
     (license license:asl2.0)))
 
-(define-public go-github-com-mattn-go-pointer
-  (let ((commit "a0a44394634f41e4992b173b24f14fecd3318a67")
-        (revision "1"))
-    (package
-      (name "go-github-com-mattn-go-pointer")
-      (version (git-version "0.0.0" revision commit))
-      (source
-       (origin
-         (method git-fetch)
-         (uri (git-reference
-               (url "https://github.com/mattn/go-pointer")
-               (commit commit)))
-         (sha256
-          (base32
-           "09w7hcyc0zz2g23vld6jbcmq4ar27xakp1ldjvh549i5izf2anhz"))
-         (file-name (git-file-name name version))))
-      (build-system go-build-system)
-      (arguments
-       '(#:import-path "github.com/mattn/go-pointer"))
-      (home-page "https://github.com/mattn/go-pointer")
-      (synopsis "Utility for cgo")
-      (description
-       "This package allows for a cgo argument to be passed a Go pointer.")
-      (license license:expat))))
-
 (define-public go-github-com-mgutz-ansi
   (let ((commit "9520e82c474b0a04dd04f8a40959027271bab992")
         (revision "0"))