gnu: Use 'mirror://' URLs in several places.

* gnu/packages/emacs.scm (m17n-lib)[source]: Use 'mirror://'.
* gnu/packages/games.scm (extremetuxracer)[source]: Likewise.
* gnu/packages/gcc.scm (%gcc-infrastructure): Likewise.
* gnu/packages/gtk.scm (python2-pygtk)[source]: Likewise.
* gnu/packages/perl.scm (perl)[source]: Likewise.
* gnu/packages/telephony.scm (exosip)[source]: Likewise.
* gnu/packages/wm.scm (xmonad)[source]: Likewise.
(ghc-xmonad-contrib)[source]: Likewise.

gnu/packages/emacs.scm

@@ -3355,8 +3355,7 @@ This package contains the library database.")
     (source
      (origin
        (method url-fetch)
-       (uri (string-append
+       (uri (string-append "mirror://savannah/m17n/m17n-lib-"
-             "http://download.savannah.gnu.org/releases/m17n/m17n-lib-"
                            version ".tar.gz"))
        (sha256
         (base32 "10yv730i25g1rpzv6q49m6xn4p8fjm7jdwvik2h70sn8w3hm7f4f"))))

gnu/packages/games.scm

@@ -946,7 +946,7 @@ Protocol).")
     (source (origin
               (method url-fetch)
               (uri (string-append
-                    "http://downloads.sourceforge.net/project/extremetuxracer/releases/"
+                    "mirror://sourceforge/extremetuxracer/releases/"
                     version "/etr-" version ".tar.xz"))
               (sha256
                (base32

gnu/packages/gcc.scm

@@ -45,7 +45,7 @@
 
 (define %gcc-infrastructure
   ;; Base URL for GCC's infrastructure.
-  "ftp://gcc.gnu.org/pub/gcc/infrastructure/")
+  "mirror://gcc/infrastructure/")
 
 (define (gcc-configure-flags-for-triplet target)
   "Return a list of additional GCC `configure' flags for TARGET, a GNU triplet.

gnu/packages/gtk.scm

@@ -1116,7 +1116,7 @@ extensive documentation, including API reference and a tutorial.")
     (source
      (origin
       (method url-fetch)
-      (uri (string-append "http://ftp.gnome.org/pub/GNOME/sources"
+      (uri (string-append "mirror://gnome/sources"
                           "/pygtk/" (version-major+minor version)
                           "/pygtk-" version ".tar.bz2"))
       (sha256

gnu/packages/perl.scm

@@ -48,7 +48,7 @@
     (version "5.24.0")
     (source (origin
              (method url-fetch)
-             (uri (string-append "http://www.cpan.org/src/5.0/perl-"
+             (uri (string-append "mirror://cpan/src/5.0/perl-"
                                  version ".tar.gz"))
              (sha256
               (base32

gnu/packages/telephony.scm

@@ -134,8 +134,7 @@ to initiate and control SIP sessions.")
    (version "4.1.0")
    (source (origin
             (method url-fetch)
-            (uri (string-append
+            (uri (string-append "mirror://savannah/exosip/libeXosip2-"
-                  "http://download.savannah.gnu.org/releases/exosip/libeXosip2-"
                                 version ".tar.gz"))
             (sha256 (base32
                      "17cna8kpc8nk1si419vgr6r42k2lda0rdk50vlxrw8rzg0xp2xrw"))))

gnu/packages/wm.scm

@@ -299,7 +299,7 @@ prompt.")
     (synopsis "Tiling window manager")
     (source (origin
               (method url-fetch)
-              (uri (string-append "http://hackage.haskell.org/package/xmonad/"
+              (uri (string-append "mirror://hackage/package/xmonad/"
                                   name "-" version ".tar.gz"))
               (sha256
                (base32
@@ -355,7 +355,7 @@ tiled on several screens.")
     (source
      (origin
        (method url-fetch)
-       (uri (string-append "http://hackage.haskell.org/package/xmonad-contrib/"
+       (uri (string-append "mirror://hackage/package/xmonad-contrib/"
                            "xmonad-contrib-" version ".tar.gz"))
        (sha256
         (base32