gnu: gcc: Use `gcc-configure-flags-for-triplet' when cross-compiling GCC.

* gnu/packages/cross-base.scm (gcc-configure-flags-for-triplet): Move to...
* gnu/packages/gcc.scm (gcc-configure-flags-for-triplet): ... here.  New
  procedure.
  (gcc-4.7): Use it when (%current-target-system) is true.

gnu/packages/cross-base.scm

@@ -30,7 +30,6 @@ (define-module (gnu packages cross-base)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-26)
   #:use-module (ice-9 match)
-  #:use-module (ice-9 regex)
   #:export (cross-binutils
             cross-libc
             cross-gcc))
@@ -66,20 +65,6 @@ (define (cross-binutils target)
                         `(cons "--with-sysroot=/" ,flags)))))))
     (cross binutils target)))
 
-(define (gcc-configure-flags-for-triplet target)
-  "Return a list of additional GCC `configure' flags for TARGET, a GNU triplet.
-
-The purpose of this procedure is to translate extended GNU triplets---e.g.,
-where the OS part is overloaded to denote a specific ABI---into GCC
-`configure' options.  We take extended GNU triplets that glibc recognizes."
-  (cond ((string-match "^mips64el.*gnuabin?64$" target)
-         ;; Triplets recognized by glibc as denoting the N64 ABI; see
-         ;; ports/sysdeps/mips/preconfigure.
-         '("--with-abi=64"))
-        (else
-         ;; TODO: Add `armel.*gnueabi', `hf', etc.
-         '())))
-
 (define* (cross-gcc target
                     #:optional (xbinutils (cross-binutils target)) libc)
   "Return a cross-compiler for TARGET, where TARGET is a GNU triplet.  Use

gnu/packages/gcc.scm

@@ -25,12 +25,27 @@ (define-module (gnu packages gcc)
   #:use-module (gnu packages multiprecision)
   #:use-module (guix packages)
   #:use-module (guix download)
-  #:use-module (guix build-system gnu))
+  #:use-module (guix build-system gnu)
+  #:use-module (ice-9 regex))
 
 (define %gcc-infrastructure
   ;; Base URL for GCC's infrastructure.
   "ftp://gcc.gnu.org/pub/gcc/infrastructure/")
 
+(define-public (gcc-configure-flags-for-triplet target)
+  "Return a list of additional GCC `configure' flags for TARGET, a GNU triplet.
+
+The purpose of this procedure is to translate extended GNU triplets---e.g.,
+where the OS part is overloaded to denote a specific ABI---into GCC
+`configure' options.  We take extended GNU triplets that glibc recognizes."
+  (cond ((string-match "^mips64el.*gnuabin?64$" target)
+         ;; Triplets recognized by glibc as denoting the N64 ABI; see
+         ;; ports/sysdeps/mips/preconfigure.
+         '("--with-abi=64"))
+        (else
+         ;; TODO: Add `armel.*gnueabi', `hf', etc.
+         '())))
+
 (define-public gcc-4.7
   (let* ((stripped? #t)                           ; TODO: make this a parameter
          (maybe-target-tools
@@ -64,6 +79,12 @@ (define-public gcc-4.7
                                            "/include")
                             "--without-headers")))
 
+                   ;; When cross-compiling GCC, pass the right options for the
+                   ;; target triplet.
+                   (or (and=> (%current-target-system)
+                              gcc-configure-flags-for-triplet)
+                       '())
+
                    (maybe-target-tools))))))
     (package
       (name "gcc")