When passing an absolute file path to yacc, we would skip
initializing inpath, leaving it null. This would cause Bopen
to die. We would similarly fail to report an error if we tried
to get the current working directory, and then die when
constructing inpath.
This fixes both cases.
as the generated parser intermixes lines from .y source
and the parser text, the line source/lineno for yyparse()
shows up wrong in the debugger. to make stack traces a
bit less crazy, put a #line 1 "/sys/lib/yaccpar" before
copying in the parser text.
