Makefile error: redefinition of enumerator

[BaseMax]

Hi,

[max@base compiler]$ make

bison -d parser.y
parser.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
flex lexer.l
clang -Wall -g   -c -o lex.yy.o lex.yy.c
In file included from lexer.l:2:
parser.y:15:5: warning: declaration does not declare anything [-Wmissing-declarations]
    struct AST;
    ^
parser.y:16:5: warning: declaration does not declare anything [-Wmissing-declarations]
    struct list;
    ^
2 warnings generated.
clang -Wall -g   -c -o parser.tab.o parser.tab.c
parser.tab.c:131:5: error: redefinition of enumerator 'RETURN'
    RETURN = 262,                  /* RETURN  */
    ^
./ast.h:12:19: note: previous definition is here
    ARRAY_ACCESS, RETURN,
                  ^
parser.tab.c:132:5: error: redefinition of enumerator 'WHILE'
    WHILE = 263,                   /* WHILE  */
    ^
./ast.h:13:5: note: previous definition is here
    WHILE, IF_THEN,
    ^
parser.y:15:5: warning: declaration does not declare anything [-Wmissing-declarations]
    struct AST;
    ^
parser.y:16:5: warning: declaration does not declare anything [-Wmissing-declarations]
    struct list;
    ^
2 warnings and 2 errors generated.
make: *** [<builtin>: parser.tab.o] Error 1

Regards,
Max