gnu: Add go-github-com-niemeyer-pretty.

* gnu/packages/golang.scm (go-github-com-niemeyer-pretty): New variable.

gnu/packages/golang.scm

@@ -5511,6 +5511,35 @@ format in Go.")
     (home-page "https://github.com/kr/pretty")
     (license license:expat)))
 
+(define-public go-github-com-niemeyer-pretty
+  (package
+    (name "go-github-com-niemeyer-pretty")
+    (version "0.0.0-20200227124842-a10e7caefd8e")
+    (source
+      (origin
+        (method git-fetch)
+        (uri (git-reference
+               (url "https://github.com/niemeyer/pretty")
+               (commit (go-version->git-ref version))))
+        (file-name (git-file-name name version))
+        (sha256
+         (base32 "1jmazh4xzaa3v6g46hz60q2z7nmqs9l9cxdzmmscn3kbcs2znq4v"))
+        (modules '((guix build utils)))
+        (snippet
+         '(begin
+            ;; https://github.com/kr/pretty/pull/66
+            (substitute* "formatter.go"
+              (("string\\(i\\)") "string(rune(i))"))))))
+    (build-system go-build-system)
+    (arguments
+     '(#:import-path "github.com/niemeyer/pretty"))
+    (propagated-inputs
+     (list go-github-com-kr-text))
+    (home-page "https://github.com/niemeyer/pretty")
+    (synopsis "Pretty printer for Go values")
+    (description "This package provides a pretty printer for Go values.")
+    (license license:expat)))
+
 (define-public go-github-com-kylelemons-godebug
   (package
     (name "go-github-com-kylelemons-godebug")