Parsing support for multiple keysyms per entry

Instead of allowing only one keysym per level per group, do as the
external API indicates and allow multiples.  The existing syntax is:
    key <AD01> { [ q, Q ] };
where the new syntax is:
    key <AD01> { [ q, Q, { H, E, L, L, O },
                 { Y, E, S, space, T, H, I, S, space, I, S, space, D, O, G } };

to make the key in the extreme top left of the keyboard do pretty
surprising things in levels 3 and 4.

Signed-off-by: Daniel Stone <daniel@fooishbar.org>

src/xkbcomp/xkbparse.y

@@ -145,7 +145,7 @@ extern int yylex(union YYSTYPE *val, struct YYLTYPE *loc, void *scanner);
 %type <str>	KeyName MapName OptMapName KeySym
 %type <sval>	FieldSpec Ident Element String
 %type <any>	DeclList Decl
-%type <expr>	OptExprList ExprList Expr Term Lhs Terminal ArrayInit
+%type <expr>	OptExprList ExprList Expr Term Lhs Terminal ArrayInit KeySyms
 %type <expr>	OptKeySymList KeySymList Action ActionList Coord CoordList
 %type <var>	VarDecl VarDeclList SymbolsBody SymbolsVarDecl
 %type <vmod>	VModDecl VModDefList VModDef
@@ -722,8 +722,19 @@ OptKeySymList	:	KeySymList			{ $$= $1; }
 
 KeySymList	:	KeySymList COMMA KeySym
 			{ $$= AppendKeysymList($1,$3); }
+                |       KeySymList COMMA KeySyms
+                        {
+                            $$= AppendKeysymList($1, strdup("NoSymbol"));
+                            FreeStmt(&$3->common);
+                        }
 		|	KeySym
 			{ $$= CreateKeysymList($1); }
+                |       KeySyms
+                        { $$= CreateKeysymList(strdup("NoSymbol")); }
+		;
+
+KeySyms         :       OBRACE KeySymList CBRACE
+                        { $$= $2; }
                 ;
 
 KeySym		:	IDENT	{ $$= $1; }