The "%expect 0" construct will make bison emit an error if any future
changes to the grammar introduce shift/reduce conflicts, (without also
increasing the number after "%expect").
Since we have productions to turn "defined FOO" and "defined ( FOO )"
into a conditional_token we don't need to list DEFINED as an operator
as well. Doing so just introduces the shift/reduce ambiguity with no
benefit.
It's really hard to believe that this case has been broken, but apparently
no test previously exercised it. So this commit adds such a test and fixes
it by making a copy of the argument token-list before expanding it.
This fix causes the following glean tests to now pass:
glsl1-Preprocessor test 6 (#if 0, #define macro)
glsl1-Preprocessor test 7 (multi-line #define)
Consider this test case:
#define EMPTY
int foo = 1+EMPTY+4;
The expression should compile as the sequence of tokens 1, PLUS,
UNARY_POSITIVE, 4. But glcpp has been failing for this case since it
results in the string "1++4" which a compiler correctly sees as a
syntax error, (1, POST_INCREMENT, 4).
We fix this by changing any macro with an empty definition to result
in a single SPACE token rather than nothing. This then gives "1+ +4"
which compiles correctly.
This commit does touch up the two existing test cases which already
have empty macros, (to add the space to the expected result).
It also adds a new test case to exercise the above scenario.
Currently only GL_ARB_draw_buffers and GL_ARB_texture_rectangle are
defined because those extensions are always enabled. This make
tex_rect-03.frag pass.
