gnu: coreutils: Fix cross-compilation.

* gnu/packages/patches/coreutils-fix-cross-compilation.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/base.scm (coreutils)[source]: Use it.

gnu/local.mk

@@ -510,6 +510,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/clx-remove-demo.patch			\
   %D%/packages/patches/cmake-fix-tests.patch			\
   %D%/packages/patches/coda-use-system-libs.patch		\
+  %D%/packages/patches/coreutils-fix-cross-compilation.patch    \
   %D%/packages/patches/cpio-CVE-2016-2037.patch			\
   %D%/packages/patches/cpufrequtils-fix-aclocal.patch		\
   %D%/packages/patches/cracklib-CVE-2016-6318.patch		\

gnu/packages/base.scm

@@ -291,7 +291,8 @@ used to apply commands with arbitrarily long arguments.")
                                 version ".tar.xz"))
             (sha256
              (base32
-              "13lspazc7xkviy93qz7ks9jv4sldvgmwpq36ghrbrqpq93br8phm"))))
+              "13lspazc7xkviy93qz7ks9jv4sldvgmwpq36ghrbrqpq93br8phm"))
+            (patches (search-patches "coreutils-fix-cross-compilation.patch"))))
    (build-system gnu-build-system)
    (inputs `(("acl"  ,acl)                        ; TODO: add SELinux
              ("gmp"  ,gmp)                        ;bignums in 'expr', yay!

gnu/packages/patches/coreutils-fix-cross-compilation.patch

@@ -0,0 +1,15 @@
+Coreutils fails to cross compile for other platforms because cu_install_program
+is not being evaluated properly. This patch fixes it.
+See <https://lists.gnu.org/archive/html/coreutils/2017-01/msg00039.html>
+--- a/Makefile.in
++++ b/Makefile.in
+@@ -5023,7 +5023,7 @@ pr = progs-readme
+ @CROSS_COMPILING_FALSE@cu_install_program = src/ginstall
+ 
+ # Use the just-built 'ginstall', when not cross-compiling.
+-@CROSS_COMPILING_TRUE@cu_install_program = @INSTALL_PROGRAM@
++@CROSS_COMPILING_TRUE@cu_install_program := @INSTALL@
+ info_TEXINFOS = doc/coreutils.texi
+ doc_coreutils_TEXINFOS = \
+   doc/perm.texi \
+