gnu: Add arm-none-eabi cross compiler.

* gnu/packages/bootstrap.scm (glibc-dynamic-linker): Add case for "arm-eabi".
* gnu/packages/embedded.scm: New file.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add it.

gnu/local.mk

@@ -110,6 +110,7 @@ GNU_SYSTEM_MODULES =				\
   %D%/packages/education.scm			\
   %D%/packages/elf.scm				\
   %D%/packages/elixir.scm			\
+  %D%/packages/embedded.scm			\
   %D%/packages/emacs.scm			\
   %D%/packages/enchant.scm			\
   %D%/packages/engineering.scm			\

gnu/packages/bootstrap.scm

@@ -171,6 +171,7 @@ successful, or false to signal an error."
 
         ;; XXX: This one is used bare-bones, without a libc, so add a case
         ;; here just so we can keep going.
+        ((string=? system "arm-eabi") "no-ld.so")
         ((string=? system "xtensa-elf") "no-ld.so")
         ((string=? system "avr") "no-ld.so")
         ((string=? system "i686-mingw") "no-ld.so")

gnu/packages/embedded.scm

@@ -0,0 +1,98 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2016 Ricardo Wurmus <rekado@elephly.net>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (gnu packages embedded)
+  #:use-module (guix utils)
+  #:use-module (guix packages)
+  #:use-module (guix download)
+  #:use-module (guix svn-download)
+  #:use-module (guix git-download)
+  #:use-module ((guix licenses) #:prefix license:)
+  #:use-module (guix build-system gnu)
+  #:use-module (gnu packages)
+  #:use-module (gnu packages cross-base)
+  #:use-module (gnu packages flex)
+  #:use-module (gnu packages perl)
+  #:use-module (gnu packages texinfo))
+
+;; We must not use the released GCC sources here, because the cross-compiler
+;; does not produce working binaries.  Instead we take the very same SVN
+;; revision from the branch that is used for a release of the "GCC ARM
+;; embedded" project on launchpad.
+;; See https://launchpadlibrarian.net/218827644/release.txt
+(define-public gcc-arm-none-eabi-4.9
+  (let ((xgcc (cross-gcc "arm-none-eabi"
+                         (cross-binutils "arm-none-eabi")))
+        (revision "1")
+        (svn-revision 227977))
+    (package (inherit xgcc)
+      (version (string-append (package-version xgcc) "-"
+                              revision "." (number->string svn-revision)))
+      (source
+       (origin
+         (method svn-fetch)
+         (uri (svn-reference
+               (url "svn://gcc.gnu.org/svn/gcc/branches/ARM/embedded-4_9-branch/")
+               (revision svn-revision)))
+         (file-name (string-append "gcc-arm-embedded-" version "-checkout"))
+         (sha256
+          (base32
+           "113r98kygy8rrjfv2pd3z6zlfzbj543pq7xyq8bgh72c608mmsbr"))
+         (patches (origin-patches (package-source xgcc)))))
+      (native-inputs
+       `(("flex" ,flex)
+         ,@(package-native-inputs xgcc)))
+      (arguments
+       (substitute-keyword-arguments (package-arguments xgcc)
+         ((#:phases phases)
+          `(modify-phases ,phases
+             (add-after 'unpack 'fix-genmultilib
+               (lambda _
+                 (substitute* "gcc/genmultilib"
+                   (("#!/bin/sh") (string-append "#!" (which "sh"))))
+                 #t))))
+         ((#:configure-flags flags)
+          ;; The configure flags are largely identical to the flags used by the
+          ;; "GCC ARM embedded" project.
+          `(append (list "--enable-multilib"
+                         "--with-newlib"
+                         "--with-multilib-list=armv6-m,armv7-m,armv7e-m"
+                         "--with-host-libstdcxx=-static-libgcc -Wl,-Bstatic,-lstdc++,-Bdynamic -lm"
+                         "--enable-plugins"
+                         "--disable-decimal-float"
+                         "--disable-libffi"
+                         "--disable-libgomp"
+                         "--disable-libmudflap"
+                         "--disable-libquadmath"
+                         "--disable-libssp"
+                         "--disable-libstdcxx-pch"
+                         "--disable-nls"
+                         "--disable-shared"
+                         "--disable-threads"
+                         "--disable-tls")
+                   (delete "--disable-multilib" ,flags)))))
+      (native-search-paths
+       (list (search-path-specification
+              (variable "CROSS_C_INCLUDE_PATH")
+              (files '("arm-none-eabi/include")))
+             (search-path-specification
+              (variable "CROSS_CPLUS_INCLUDE_PATH")
+              (files '("arm-none-eabi/include")))
+             (search-path-specification
+              (variable "CROSS_LIBRARY_PATH")
+              (files '("arm-none-eabi/lib"))))))))