Fix ecpg's mishandling of B'...' and X'...' literals.
These were broken in multiple ways:
* The xbstart and xhstart lexer actions neglected to set
"state_before_str_start" before transitioning to the xb/xh states,
thus possibly resulting in "internal error: unreachable state" later.
* The test f
Fix ecpg's mishandling of B'...' and X'...' literals.
These were broken in multiple ways:
* The xbstart and xhstart lexer actions neglected to set
"state_before_str_start" before transitioning to the xb/xh states,
thus possibly resulting in "internal error: unreachable state" later.
* The test f
