cp: implement -T

Implement "cp -T". Some Linux kernel Makefiles started using this recently,
so allow also building on systems using busybox cp.

function                                             old     new   delta
cp_main                                              360     428     +68
copy_file                                           1678    1676      -2
packed_usage                                       32290   32259     -31
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/2 up/down: 76/-39)             Total: 35 bytes

Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/coreutils/cp.c b/coreutils/cp.c
index 05c725c..8d93c6f 100644
--- a/coreutils/cp.c
+++ b/coreutils/cp.c
@@ -48,6 +48,7 @@
 //usage:     "\n	-f	Overwrite"
 //usage:     "\n	-i	Prompt before overwrite"
 //usage:     "\n	-l,-s	Create (sym)links"
+//usage:     "\n	-T	Treat DEST as a normal file"
 //usage:     "\n	-u	Copy only newer files"
 
 #include "libbb.h"
@@ -93,6 +94,7 @@
 		"no-dereference\0" No_argument "P"
 		"recursive\0"      No_argument "R"
 		"symbolic-link\0"  No_argument "s"
+		"no-target-directory\0" No_argument "T"
 		"verbose\0"        No_argument "v"
 		"update\0"         No_argument "u"
 		"remove-destination\0" No_argument "\xff"
@@ -122,6 +124,8 @@
 	 *	remove each existing destination file before attempting to open
 	 * --parents
 	 *	use full source file name under DIRECTORY
+	 * -T, --no-target-directory
+	 *	treat DEST as a normal file
 	 * NOT SUPPORTED IN BBOX:
 	 * --backup[=CONTROL]
 	 *	make a backup of each existing destination file
@@ -140,8 +144,6 @@
 	 *	override the usual backup suffix
 	 * -t, --target-directory=DIRECTORY
 	 *	copy all SOURCE arguments into DIRECTORY
-	 * -T, --no-target-directory
-	 *	treat DEST as a normal file
 	 * -x, --one-file-system
 	 *	stay on this file system
 	 * -Z, --context=CONTEXT
@@ -176,6 +178,12 @@
 		if (d_flags < 0)
 			return EXIT_FAILURE;
 
+		if (flags & FILEUTILS_NO_TARGET_DIR) { /* -T */
+			if (!(s_flags & 2) && (d_flags & 2))
+				/* cp -T NOTDIR DIR */
+				bb_error_msg_and_die("'%s' is a directory", last);
+		}
+
 #if ENABLE_FEATURE_CP_LONG_OPTIONS
 		//bb_error_msg("flags:%x FILEUTILS_RMDEST:%x OPT_parents:%x",
 		//	flags, FILEUTILS_RMDEST, OPT_parents);
@@ -193,11 +201,14 @@
 		if (!((s_flags | d_flags) & 2)
 		    /* ...or: recursing, the 1st is a directory, and the 2nd doesn't exist... */
 		 || ((flags & FILEUTILS_RECUR) && (s_flags & 2) && !d_flags)
+		 || (flags & FILEUTILS_NO_TARGET_DIR)
 		) {
 			/* Do a simple copy */
 			dest = last;
 			goto DO_COPY; /* NB: argc==2 -> *++argv==last */
 		}
+	} else if (flags & FILEUTILS_NO_TARGET_DIR) {
+		bb_error_msg_and_die("too many arguments");
 	}
 
 	while (1) {