copy_file: handle "cp /dev/foo file" (almost) compatibly to coreutils.
(almost because we do not copy mode, which is probably wasn't intended).
+61 bytes.
diff --git a/testsuite/cp/cp-a-files-to-dir b/testsuite/cp/cp-a-files-to-dir
index 39f8f81..abdbdf7 100644
--- a/testsuite/cp/cp-a-files-to-dir
+++ b/testsuite/cp/cp-a-files-to-dir
@@ -2,7 +2,8 @@
echo file number two > file2
ln -s file2 link1
mkdir dir1
-touch --date='Sat Jan 29 21:24:08 PST 2000' dir1/file3
+# why???
+#touch --date='Sat Jan 29 21:24:08 PST 2000' dir1/file3
mkdir there
busybox cp -a file1 file2 link1 dir1 there
test -f there/file1