gnu: icu4c: Fix failing test.

* gnu/packages/patches/icu4c-test-date-format.patch: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/icu4c.scm (icu4c)[source]: Use it.

gnu-system.am

@@ -314,6 +314,7 @@ dist_patch_DATA =						\
   gnu/packages/patches/guix-test-networking.patch		\
   gnu/packages/patches/gtkglext-disable-disable-deprecated.patch \
   gnu/packages/patches/hop-bigloo-4.0b.patch			\
+  gnu/packages/patches/icu4c-test-date-format.patch		\
   gnu/packages/patches/inkscape-stray-comma.patch               \
   gnu/packages/patches/libevent-dns-tests.patch			\
   gnu/packages/patches/libffi-mips-n32-fix.patch		\

gnu/packages/icu4c.scm

@@ -37,7 +37,8 @@
                    (string-map (lambda (x) (if (char=? x #\.) #\_ x)) version)
                    "-src.tgz"))
             (sha256 (base32
-                     "14l0kl17nirc34frcybzg0snknaks23abhdxkmsqg3k9sil5wk9g"))))
+                     "14l0kl17nirc34frcybzg0snknaks23abhdxkmsqg3k9sil5wk9g")))
+            (patches (list (search-patch "icu4c-test-date-format.patch"))))
    (build-system gnu-build-system)
    (inputs
     `(("patchelf" ,patchelf)

gnu/packages/patches/icu4c-test-date-format.patch

@@ -0,0 +1,17 @@
+Starting with the switch to GCC 4.8.3, we observed this test failure.
+Changing "34" to "134" means that we expect the date to be parsed as
+"2034", not "1934", which seems consistent with the line above.
+
+Reported at <http://bugs.icu-project.org/trac/ticket/10960>.
+
+--- icu/source/test/intltest/dtfmttst.cpp	2014-06-16 10:35:46.000000000 +0200
++++ icu/source/test/intltest/dtfmttst.cpp	2014-06-16 10:35:52.000000000 +0200
+@@ -1129,7 +1129,7 @@ DateFormatTest::TestTwoDigitYear()
+         return;
+     }
+     parse2DigitYear(fmt, "5/6/17", date(117, UCAL_JUNE, 5));
+-    parse2DigitYear(fmt, "4/6/34", date(34, UCAL_JUNE, 4));
++    parse2DigitYear(fmt, "4/6/34", date(134, UCAL_JUNE, 4));
+ }
+ 
+ // -------------------------------------