N'xxx' and _utf8'xxx' are not equivalent

Problem: Unescaping of '\' characters didn't work when processing N'xxx'.
Fix: using get_text() instead of get_token() when scanning nationa strings.

mysql-test/r/ctype_utf8.result

@@ -1066,6 +1066,18 @@ LENGTH(bug)
 100
 DROP TABLE t2;
 DROP TABLE t1;
+CREATE TABLE t1 (item varchar(255)) default character set utf8;
+INSERT INTO t1 VALUES (N'\\');
+INSERT INTO t1 VALUES (_utf8'\\');
+INSERT INTO t1 VALUES (N'Cote d\'Ivoire');
+INSERT INTO t1 VALUES (_utf8'Cote d\'Ivoire');
+SELECT item FROM t1 ORDER BY item;
+item
+Cote d'Ivoire
+Cote d'Ivoire
+\
+\
+DROP TABLE t1;
 SET NAMES utf8;
 DROP TABLE IF EXISTS t1;
 Warnings:

mysql-test/t/ctype_utf8.test

@@ -878,6 +878,17 @@ SELECT LENGTH(bug) FROM t2;
 DROP TABLE t2;
 DROP TABLE t1;
 
+#
+# Bug#17313: N'xxx' and _utf8'xxx' are not equivalent
+#
+CREATE TABLE t1 (item varchar(255)) default character set utf8;
+INSERT INTO t1 VALUES (N'\\');
+INSERT INTO t1 VALUES (_utf8'\\');
+INSERT INTO t1 VALUES (N'Cote d\'Ivoire');
+INSERT INTO t1 VALUES (_utf8'Cote d\'Ivoire');
+SELECT item FROM t1 ORDER BY item;
+DROP TABLE t1;
+
 #
 # Bug#17705: Corruption of compressed index when index length changes between
 # 254 and 256

sql/sql_lex.cc

@@ -557,23 +557,20 @@ int MYSQLlex(void *arg, void *yythd)
 
     case MY_LEX_IDENT_OR_NCHAR:
       if (yyPeek() != '\'')
-      {					// Found x'hex-number'
+      {					
 	state= MY_LEX_IDENT;
 	break;
       }
-      yyGet();				// Skip '
-      while ((c = yyGet()) && (c !='\'')) ;
-      length=(lex->ptr - lex->tok_start);	// Length of hexnum+3
-      if (c != '\'')
+      /* Found N'string' */
+      lex->tok_start++;                 // Skip N
+      yySkip();                         // Skip '
+      if (!(yylval->lex_str.str = get_text(lex)))
       {
-	return(ABORT_SYM);		// Illegal hex constant
+	state= MY_LEX_CHAR;             // Read char by char
+	break;
       }
-      yyGet();				// get_token makes an unget
-      yylval->lex_str=get_token(lex,length);
-      yylval->lex_str.str+=2;		// Skip x'
-      yylval->lex_str.length-=3;	// Don't count x' and last '
-      lex->yytoklen-=3;
-      return (NCHAR_STRING);
+      yylval->lex_str.length= lex->yytoklen;
+      return(NCHAR_STRING);
 
     case MY_LEX_IDENT_OR_HEX:
       if (yyPeek() == '\'')