This commit decreases 6 shift/reduce conflicts, and finally achieves
conflict-free parser.
Since Kconfig has no terminator for a config block, detecting the end
of config_stmt is not easy.
For example, there are two ways for handling the error in the following
code:
1 config FOO
2 =
[A] Print "unknown option" error, assuming the line 2 is a part of
config_option_list
[B] Print "invalid statement", assuming the line 1 is reduced into
a config_stmt by itself
Bison actually chooses [A] because it performs the shift rather than
the reduction where both are possible.
However, there is no reason to choose one over the other.
Let's remove the option_error, and let it fall back to [B].
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>