libbb: introduce and use strcpy_and_process_escape_sequences

function                                             old     new   delta
strcpy_and_process_escape_sequences                    -      50     +50
bb_process_escape_sequence                           148     138     -10
printf_main                                          789     776     -13
getty_main                                          1897    1831     -66
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/3 up/down: 50/-89)            Total: -39 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/e2fsprogs/old_e2fsprogs/fsck.c b/e2fsprogs/old_e2fsprogs/fsck.c
index 524b846..3a0743b 100644
--- a/e2fsprogs/old_e2fsprogs/fsck.c
+++ b/e2fsprogs/old_e2fsprogs/fsck.c
@@ -349,15 +349,7 @@
 	if (!word)
 		return;
 
-	for (p = q = word; *p; q++) {
-		c = *p++;
-		if (c != '\\') {
-			*q = c;
-		} else {
-			*q = bb_process_escape_sequence(&p);
-		}
-	}
-	*q = 0;
+	strcpy_and_process_escape_sequences(word, word);
 }
 
 static void free_instance(struct fsck_instance *i)