mesa: f3319561a476bd806005551251dbc6a37f266e03 (master)

GLSL code that has a redefinition with a valueless macro trigger a segmentation fault in the preprocessor.

Two test cases were committed as 092-redefine-macro-error-2.c.

mesa/src/glsl/glcpp/tests/092-redefine-macro-error-2.c
     1	#define A
     2	#define A 1
     3	
     4	#define B 1
     5	#define B

$ cd mesa/src/glsl/glcpp/tests
$ ./glcpp 092-redefine-macro-error-2.c

(gdb) bt
#0  0x080502fb in _token_list_equal_ignoring_space (a=0x8a4fa78, b=0x0)
    at glcpp/glcpp-parse.y:833
#1  0x08051905 in _macro_equal (a=0x8a4faf8, b=0x8a4f918) at glcpp/glcpp-parse.y:1640
#2  0x080519db in _define_object_macro (parser=0x8a3f0e0, loc=0xbfd464d0, 
    identifier=0x8a4f9b0 "A", replacements=0x8a4fa78) at glcpp/glcpp-parse.y:1664
#3  0x0804e064 in yyparse (parser=0x8a3f0e0) at glcpp/glcpp-parse.y:217
#4  0x08050d40 in glcpp_parser_parse (parser=0x8a3f0e0) at glcpp/glcpp-parse.y:1118
#5  0x0805245f in preprocess (talloc_ctx=0x8a3d038, shader=0xbfd47e1c, info_log=0xbfd47e20, 
    extensions=0x0, api=0) at glcpp/pp.c:154
#6  0x080527c4 in main (argc=2, argv=0xbfd47ef4) at glcpp/glcpp.c:123
(gdb) frame 0
#0  0x080502fb in _token_list_equal_ignoring_space (a=0x8a4fa78, b=0x0)
    at glcpp/glcpp-parse.y:833
833		node_b = b->head;