gnu: valgrind: Fix build against glibc 2.21

* gnu/packages/patches/valgrind-glibc-2.21.patch: New file.
* gnu-system.am (dist_patch_DATA): Add patch.
* gnu/packages/valgrind.scm (valgrind): Apply patch.

gnu-system.am

@@ -529,6 +529,7 @@ dist_patch_DATA =						\
   gnu/packages/patches/unzip-CVE-2014-8140.patch		\
   gnu/packages/patches/unzip-CVE-2014-8141.patch		\
   gnu/packages/patches/util-linux-tests.patch			\
+  gnu/packages/patches/valgrind-glibc-2.21.patch		\
   gnu/packages/patches/vpnc-script.patch			\
   gnu/packages/patches/vtk-mesa-10.patch			\
   gnu/packages/patches/w3m-fix-compile.patch			\

gnu/packages/patches/valgrind-glibc-2.21.patch

@@ -0,0 +1,26 @@
+Submitted By: Pierre Labastie <pierre at linuxfromscratch dot org>
+Date: 2015-02-22
+Initial Package Version: 3.10.1
+Upstream Status: Unknown
+Origin: Self
+Description: Allows Valgrind to build with glibc-2.21
+diff -Naur valgrind-3.10.1.old/configure valgrind-3.10.1.new/configure
+--- valgrind-3.10.1.old/configure	2014-11-25 20:42:25.000000000 +0100
++++ valgrind-3.10.1.new/configure	2015-02-22 10:46:06.607826488 +0100
+@@ -6842,6 +6842,16 @@
+ 	DEFAULT_SUPP="glibc-2.34567-NPTL-helgrind.supp ${DEFAULT_SUPP}"
+ 	DEFAULT_SUPP="glibc-2.X-drd.supp ${DEFAULT_SUPP}"
+ 	;;
++     2.21)
++	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: 2.21 family" >&5
++$as_echo "2.21 family" >&6; }
++
++$as_echo "#define GLIBC_2_21 1" >>confdefs.h
++
++	DEFAULT_SUPP="glibc-2.X.supp ${DEFAULT_SUPP}"
++	DEFAULT_SUPP="glibc-2.34567-NPTL-helgrind.supp ${DEFAULT_SUPP}"
++	DEFAULT_SUPP="glibc-2.X-drd.supp ${DEFAULT_SUPP}"
++	;;
+      darwin)
+ 	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: Darwin" >&5
+ $as_echo "Darwin" >&6; }

gnu/packages/valgrind.scm

@@ -36,7 +36,8 @@
                                  version ".tar.bz2"))
              (sha256
               (base32
-               "15xrzhfnwwn7n1sfbkwvdbvs6zk0zx718n6zd5i1nrnvdp13s9gs"))))
+               "15xrzhfnwwn7n1sfbkwvdbvs6zk0zx718n6zd5i1nrnvdp13s9gs"))
+             (patches (list (search-patch "valgrind-glibc-2.21.patch")))))
     (build-system gnu-build-system)
     (arguments
      '(#:phases (alist-cons-after