gnu: gdb: Add support for the Hurd.

* gnu/packages/gdb.scm (gdb-9.1)[native-inputs]: When compiling for the Hurd,
add required build dependency mig.
["arguments"]: Add "binutils" fall-back lookup in native-inputs for
cross-builds.
* gnu/packages/patches/gdb-hurd.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/gdb.scm (gdb-9.2): Use it.

gnu/local.mk

@@ -972,6 +972,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/gcc-9-strmov-store-file-names.patch	\
   %D%/packages/patches/gd-fix-tests-on-i686.patch		\
   %D%/packages/patches/gd-brect-bounds.patch			\
+  %D%/packages/patches/gdb-hurd.patch				\
   %D%/packages/patches/gdm-default-session.patch		\
   %D%/packages/patches/geoclue-config.patch			\
   %D%/packages/patches/ghc-8.0-fall-back-to-madv_dontneed.patch	\

gnu/packages/gdb.scm

@@ -4,6 +4,7 @@
 ;;; Copyright © 2015, 2016, 2019 Efraim Flashner <efraim@flashner.co.il>
 ;;; Copyright © 2020 Marius Bakke <mbakke@fastmail.com>
 ;;; Copyright © 2020 Vincent Legoll <vincent.legoll@gmail.com>
+;;; Copyright © 2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -22,6 +23,7 @@
 
 (define-module (gnu packages gdb)
   #:use-module (gnu packages)
+  #:use-module (gnu packages hurd)
   #:use-module (gnu packages ncurses)
   #:use-module (gnu packages readline)
   #:use-module (gnu packages dejagnu)
@@ -68,12 +70,14 @@
                      #t))
                   (add-after
                    'install 'remove-libs-already-in-binutils
-                   (lambda* (#:key inputs outputs #:allow-other-keys)
+                   (lambda* (#:key inputs native-inputs outputs
+                             #:allow-other-keys)
                      ;; Like Binutils, GDB installs libbfd, libopcodes, etc.
                      ;; However, this leads to collisions when both are
                      ;; installed, and really is none of its business,
                      ;; conceptually.  So remove them.
-                     (let* ((binutils (assoc-ref inputs "binutils"))
+                     (let* ((binutils (or (assoc-ref inputs "binutils")
+                                          (assoc-ref native-inputs "binutils")))
                             (out      (assoc-ref outputs "out"))
                             (files1   (with-directory-excursion binutils
                                         (append (find-files "lib")
@@ -98,11 +102,15 @@
 
        ;; Allow use of XML-formatted syscall information.  This enables 'catch
        ;; syscall' and similar commands.
-       ("libxml2" ,libxml2)))
+       ("libxml2" ,libxml2)
+
+       ;; The Hurd needs -lshouldbeinlibc.
+       ,@(if (hurd-target?) `(("hurd" ,hurd)) '())))
     (native-inputs
       `(("texinfo" ,texinfo)
         ("dejagnu" ,dejagnu)
-        ("pkg-config" ,pkg-config)))
+        ("pkg-config" ,pkg-config)
+        ,@(if (hurd-target?) `(("mig" ,mig)) '())))
     (home-page "https://www.gnu.org/software/gdb/")
     (synopsis "The GNU debugger")
     (description
@@ -140,6 +148,7 @@ written in C, C++, Ada, Objective-C, Pascal and more.")
               (method url-fetch)
               (uri (string-append "mirror://gnu/gdb/gdb-"
                                   version ".tar.xz"))
+              (patches (search-patches "gdb-hurd.patch"))
               (sha256
                (base32
                 "0mf5fn8v937qwnal4ykn3ji1y2sxk0fa1yfqi679hxmpg6pdf31n"))))))

gnu/packages/patches/gdb-hurd.patch

@@ -0,0 +1,69 @@
+Taken from upstream, removed ChangeLog.
+
+From 6930bffe3373690b3431d6291f9f7c116d6a1ec4 Mon Sep 17 00:00:00 2001
+From: Samuel Thibault <samuel.thibault@ens-lyon.org>
+Date: Sat, 30 May 2020 18:35:59 +0000
+Subject: [PATCH] hurd: fix gnu_debug_flag type
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Fixes
+
+../../gdb/gnu-nat.c:96:6: error: conflicting declaration ‘bool gnu_debug_flag’
+   96 | bool gnu_debug_flag = false;
+../../gdb/gnu-nat.c: In function ‘void _initialize_gnu_nat()’:
+../../gdb/gnu-nat.c:3511:7: error: cannot
+
+gdb/ChangeLog:
+
+	* gnu-nat.h (gnu_debug_flag): Set type to bool.
+---
+ gdb/ChangeLog | 4 ++++
+ gdb/gnu-nat.h | 2 +-
+ 2 files changed, 5 insertions(+), 1 deletion(-)
+
+diff --git a/gdb/gnu-nat.h b/gdb/gnu-nat.h
+index 77c57817b2..766f716587 100644
+--- a/gdb/gnu-nat.h
++++ b/gdb/gnu-nat.h
+@@ -111,7 +111,7 @@ extern char *proc_string (struct proc *proc);
+ 	      __proc_pid (__proc), __proc->tid, \
+ 	      host_address_to_string (__proc) , ##args); } while (0)
+ 
+-extern int gnu_debug_flag;
++extern bool gnu_debug_flag;
+ 
+ #define debug(msg, args...) \
+  do { if (gnu_debug_flag) \
+-- 
+Jan Nieuwenhuizen <janneke@gnu.org> | GNU LilyPond http://lilypond.org
+Freelance IT http://JoyofSource.com | Avatar® http://AvatarAcademy.com
+
+commit 366f550a593c7e6bae3699a4b6d65fe937af5603
+Author: Samuel Thibault <samuel.thibault@ens-lyon.org>
+Date:   Sat May 30 18:41:30 2020 +0000
+
+    hurd: add missing include
+    
+    Fixes
+    
+    ../../gdb/gnu-nat.c:2522:14: error: ‘target_gdbarch’ was not declared in this scope; did you mean ‘target_detach’?
+     2522 |    paddress (target_gdbarch (), memaddr), pulongest (len),
+    
+    gdb/Changelog:
+    
+            * gnu-nat.c: Include "gdbarch.h".
+
+diff --git a/gdb/gnu-nat.c b/gdb/gnu-nat.c
+index 3b438a9a43..9b93488b41 100644
+--- a/gdb/gnu-nat.c
++++ b/gdb/gnu-nat.c
+@@ -64,6 +64,7 @@ extern "C"
+ #include "language.h"
+ #include "target.h"
+ #include "gdbsupport/gdb_wait.h"
++#include "gdbarch.h"
+ #include "gdbcmd.h"
+ #include "gdbcore.h"
+ #include "gdbthread.h"