MFC: r180597 Fix a longstanding bug, from Otto Moerbeck: if we're reducing a rule that has an empty right hand side and the yacc stackpointer is pointing at the very end of the allocated stack, we end up accessing the stack out of bounds by the implicit $$ = $1 action
MFC: r180597
Fix a longstanding bug, from Otto Moerbeck:
if we're reducing a rule that has an empty
right hand side and the yacc stackpointer is pointing at the very
end of the allocated stack, we end up accessing the stack out of
bounds by the implicit $$ = $1 action

Obtained from:	OpenBSD

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