gnu: readline: support mingw.

* gnu/packages/patches/readline-7.0-mingw.patch: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/readline.scm (readline): Support MinGW.

gnu/local.mk

@@ -845,6 +845,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/ratpoison-shell.patch			\
   %D%/packages/patches/readline-link-ncurses.patch		\
   %D%/packages/patches/readline-6.2-CVE-2014-2524.patch		\
+  %D%/packages/patches/readline-7.0-mingw.patch			\
   %D%/packages/patches/ripperx-missing-file.patch		\
   %D%/packages/patches/rpm-CVE-2014-8118.patch			\
   %D%/packages/patches/rsem-makefile.patch			\

gnu/packages/patches/readline-7.0-mingw.patch

@@ -0,0 +1,28 @@
+Configure checks for chown; add missing shields in code.
+
+Upstream status: not yet presented upstream.
+
+--- readline-7.0/histfile.c.orig	2016-12-06 20:04:10.058901731 +0100
++++ readline-7.0/histfile.c	2016-12-06 20:05:09.220083801 +0100
+@@ -610,8 +610,10 @@
+      user is running this, it's a no-op.  If the shell is running after sudo
+      with a shared history file, we don't want to leave the history file
+      owned by root. */
++#if HAVE_CHOWN
+   if (rv == 0 && exists)
+     r = chown (filename, finfo.st_uid, finfo.st_gid);
++#endif
+ 
+   xfree (filename);
+   FREE (tempname);
+@@ -757,8 +759,10 @@
+      user is running this, it's a no-op.  If the shell is running after sudo
+      with a shared history file, we don't want to leave the history file
+      owned by root. */
++#if HAVE_CHOWN
+   if (rv == 0 && exists)
+     mode = chown (histname, finfo.st_uid, finfo.st_gid);
++#endif
+ 
+   FREE (histname);
+   FREE (tempname);

gnu/packages/readline.scm

@@ -1,6 +1,7 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2012, 2013, 2014 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2016 Efraim Flashner <efraim@flashner.co.il>
+;;; Copyright © 2016 Jan Nieuwenhuizen <janneke@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -24,7 +25,8 @@
   #:use-module (gnu packages perl)
   #:use-module (guix packages)
   #:use-module (guix download)
-  #:use-module (guix build-system gnu))
+  #:use-module (guix build-system gnu)
+  #:use-module (guix utils))
 
 (define-public readline
   (let ((post-install-phase
@@ -61,8 +63,18 @@
                          ;; cross-compiling, so provide the correct answer.
                          ,@(if (%current-target-system)
                                '("bash_cv_wcwidth_broken=no")
+                               '())
+                         ;; MinGW: ncurses provides the termcap api.
+                         ,@(if (target-mingw?)
+                               '("bash_cv_termcap_lib=ncurses")
                                '()))
 
+                   ,@(if (target-mingw?)
+                         ;; MinGW: termcap in ncurses
+                         ;; some SIG_* #defined in _POSIX
+                         '(#:make-flags '("TERMCAP_LIB=-lncurses"
+                                          "CPPFLAGS=-D_POSIX -D'chown(f,o,g)=0'"))
+                         '())
                    #:phases (alist-cons-after
                              'install 'post-install
                              ,post-install-phase