patch: support -N. By Olivier Duclos (olivier.duclos AT gmail.com)

function                                             old     new   delta
packed_usage                                       26646   26656     +10
patch_main                                          1101    1110      +9

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/include/usage.h b/include/usage.h
index accda33..81ddbd2 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -3218,11 +3218,12 @@
 	)
 
 #define patch_trivial_usage \
-       "[-p NUM] [-i DIFF] [-R]"
+       "[-p NUM] [-i DIFF] [-R] [-N]"
 #define patch_full_usage "\n\n" \
        "	-p NUM	Strip NUM leading components from file names" \
      "\n	-i DIFF	Read DIFF instead of stdin" \
      "\n	-R	Reverse patch" \
+     "\n	-N	Ignore already applied patches" \
 
 #define patch_example_usage \
        "$ patch -p1 < example.diff\n" \