diff --git a/tools/wmc/mcl.c b/tools/wmc/mcl.c
index 99abfad0252..62cdf2534e6 100644
--- a/tools/wmc/mcl.c
+++ b/tools/wmc/mcl.c
@@ -302,7 +302,7 @@ try_again:
 
 	if(!n)
 	{
-		yywarning("Re-read line (input was or converted to zilch)");
+		mcy_warning("Re-read line (input was or converted to zilch)");
 		goto try_again;	/* Should not happen, but could be due to stdin reading and a signal */
 	}
 
@@ -490,7 +490,7 @@ static int scan_number(int ch)
 			else
 			{
 				unget_unichar(ch);
-				yylval.num = 0;
+				mcy_lval.num = 0;
 				return tNUMBER;
 			}
 			break;
@@ -535,7 +535,7 @@ static int scan_number(int ch)
 finish:
 	unget_unichar(ch);
 	push_char(0);
-	yylval.num = strtoul(get_char_stack(), NULL, base);
+	mcy_lval.num = strtoul(get_char_stack(), NULL, base);
 	return tNUMBER;
 }
 
@@ -586,7 +586,7 @@ void get_tokentable(token_t **tab, int *len)
  * The scanner
  *
  */
-int yylex(void)
+int mcy_lex(void)
 {
 	static const WCHAR ustr_dot1[] = { '.', '\n', 0 };
 	static const WCHAR ustr_dot2[] = { '.', '\r', '\n', 0 };
@@ -639,7 +639,7 @@ int yylex(void)
 				set_codepage(WMC_DEFAULT_CODEPAGE);
 				return tMSGEND;
 			}
-			yylval.str = xunistrdup(get_unichar_stack());
+			mcy_lval.str = xunistrdup(get_unichar_stack());
 			return tLINE;
 		}
 
@@ -677,7 +677,7 @@ int yylex(void)
 				unget_unichar(ch);
 				push_unichar(0);
 				want_file = 0;
-				yylval.str = xunistrdup(get_unichar_stack());
+				mcy_lval.str = xunistrdup(get_unichar_stack());
 				return tFILE;
 			}
 
@@ -693,7 +693,7 @@ int yylex(void)
 				push_unichar(0);
 				if(!(tok = lookup_token(get_unichar_stack())))
 				{
-					yylval.str = xunistrdup(get_unichar_stack());
+					mcy_lval.str = xunistrdup(get_unichar_stack());
 					return tIDENT;
 				}
 				switch(tok->type)
@@ -706,7 +706,7 @@ int yylex(void)
 					/* Fall through */
 				case tok_severity:
 				case tok_facility:
-					yylval.tok = tok;
+					mcy_lval.tok = tok;
 					return tTOKEN;
 
 				default:
@@ -738,7 +738,7 @@ int yylex(void)
 			newline();
 			push_unichar(ch);	/* Include the newline */
 			push_unichar(0);
-			yylval.str = xunistrdup(get_unichar_stack());
+			mcy_lval.str = xunistrdup(get_unichar_stack());
 			return tCOMMENT;
 		default:
 			xyyerror("Invalid character '%c' (0x%04x)", isisochar(ch) && isprint(ch) ? ch : '.', ch);
diff --git a/tools/wmc/mcy.y b/tools/wmc/mcy.y
index abe5d0253d6..fad56de67f7 100644
--- a/tools/wmc/mcy.y
+++ b/tools/wmc/mcy.y
@@ -95,8 +95,6 @@ static cp_xlat_t *find_cpxlat(int lan);
 
 %}
 
-%name-prefix="yy"
-
 %union {
 	WCHAR		*str;
 	unsigned	num;
@@ -231,7 +229,7 @@ lmap	: token '=' tNUMBER setfile ':' tFILE optcp {
 		$1->codepage = $7;
 		do_add_token(tok_language, $1, "language");
 		if(!find_language($3) && !find_cpxlat($3))
-			yywarning("Language 0x%x not built-in, using codepage %d; use explicit codepage to override", $3, WMC_DEFAULT_CODEPAGE);
+			mcy_warning("Language 0x%x not built-in, using codepage %d; use explicit codepage to override", $3, WMC_DEFAULT_CODEPAGE);
 	}
 	| token '=' tNUMBER setfile ':' error	{ xyyerror("Filename expected"); }
 	| token '=' tNUMBER error		{ xyyerror(err_colon); }
@@ -421,7 +419,7 @@ static void do_add_token(tok_e type, token_t *tok, const char *code)
 	if(tp)
 	{
 		if(tok->type != type)
-			yywarning("Type change in token");
+			mcy_warning("Type change in token");
 		if(tp != tok)
 			xyyerror("Overlapping token not the same");
 		/* else its already defined and changed */
@@ -444,7 +442,7 @@ static lanmsg_t *new_lanmsg(lan_cp_t *lcp, WCHAR *msg)
 	lmp->msg = msg;
 	lmp->len = unistrlen(msg) + 1;	/* Include termination */
 	if(lmp->len > 4096)
-		yywarning("Message exceptionally long; might be a missing termination");
+		mcy_warning("Message exceptionally long; might be a missing termination");
 	return lmp;
 }
 
diff --git a/tools/wmc/utils.c b/tools/wmc/utils.c
index 6b2de4cc279..2b3b87cd894 100644
--- a/tools/wmc/utils.c
+++ b/tools/wmc/utils.c
@@ -49,7 +49,7 @@ static void generic_msg(const char *s, const char *t, va_list ap)
  * The extra routine 'xyyerror' is used to exit after giving a real
  * message.
  */
-int yyerror(const char *s, ...)
+int mcy_error(const char *s, ...)
 {
 #ifndef SUPPRESS_YACC_ERROR_MESSAGE
 	va_list ap;
@@ -70,7 +70,7 @@ int xyyerror(const char *s, ...)
 	return 1;
 }
 
-int yywarning(const char *s, ...)
+int mcy_warning(const char *s, ...)
 {
 	va_list ap;
 	va_start(ap, s);
@@ -215,7 +215,7 @@ int unistricmp(const WCHAR *s1, const WCHAR *s2)
 			if(!once)
 			{
 				once++;
-				yywarning(warn);
+				mcy_warning(warn);
 			}
 			i = *s1++ - *s2++;
 		}
@@ -228,7 +228,7 @@ int unistricmp(const WCHAR *s1, const WCHAR *s2)
 	if((*s1 & 0xffff) > 0x7f || (*s2 & 0xffff) > 0x7f)
 	{
 		if(!once)
-			yywarning(warn);
+			mcy_warning(warn);
 		return *s1 - *s2;
 	}
 	else
diff --git a/tools/wmc/utils.h b/tools/wmc/utils.h
index 361917a05d8..5a1faf143a6 100644
--- a/tools/wmc/utils.h
+++ b/tools/wmc/utils.h
@@ -33,9 +33,9 @@ char *xstrdup(const char *str);
 #define __attribute__(X)
 #endif
 
-int yyerror(const char *s, ...) __attribute__((format (printf, 1, 2)));
+int mcy_error(const char *s, ...) __attribute__((format (printf, 1, 2)));
 int xyyerror(const char *s, ...) __attribute__((format (printf, 1, 2)));
-int yywarning(const char *s, ...) __attribute__((format (printf, 1, 2)));
+int mcy_warning(const char *s, ...) __attribute__((format (printf, 1, 2)));
 void internal_error(const char *file, int line, const char *s, ...) __attribute__((format (printf, 3, 4)));
 void error(const char *s, ...) __attribute__((format (printf, 1, 2)));
 void warning(const char *s, ...) __attribute__((format (printf, 1, 2)));
diff --git a/tools/wmc/wmc.c b/tools/wmc/wmc.c
index 4dd98895c0d..29412194833 100644
--- a/tools/wmc/wmc.c
+++ b/tools/wmc/wmc.c
@@ -113,7 +113,7 @@ int char_number = 1;		/* The current char pos within the line */
 char *cmdline;			/* The entire commandline */
 time_t now;			/* The time of start of wmc */
 
-int yydebug;
+int mcy_debug;
 
 int getopt (int argc, char *const *argv, const char *optstring);
 static void segvhandler(int sig);
@@ -239,7 +239,7 @@ int main(int argc,char *argv[])
 		return 1;
 	}
 
-	yydebug = dodebug;
+	mcy_debug = dodebug;
 	if(dodebug)
 	{
 		setbuf(stdout, 0);
@@ -273,7 +273,7 @@ int main(int argc,char *argv[])
 	else
 		yyin = stdin;
 
-	ret = yyparse();
+	ret = mcy_parse();
 
 	if(input_name)
 		fclose(yyin);
diff --git a/tools/wmc/wmc.h b/tools/wmc/wmc.h
index b18c7f05f3b..86ccd6f17fb 100644
--- a/tools/wmc/wmc.h
+++ b/tools/wmc/wmc.h
@@ -56,15 +56,15 @@ extern time_t now;
 extern int line_number;
 extern int char_number;
 
-int yyparse(void);
-extern int yydebug;
+int mcy_parse(void);
+extern int mcy_debug;
 extern int want_nl;
 extern int want_line;
 extern int want_file;
 extern node_t *nodehead;
 extern lan_blk_t *lanblockhead;
 
-int yylex(void);
+int mcy_lex(void);
 FILE *yyin;
 void set_codepage(int cp);