# Strange Bro build problem with yacc/bison
**URL:** https://community.zeek.org/t/strange-bro-build-problem-with-yacc-bison/1074
**Category:** Zeek
**Created:** [December 2, 2006, 12:20am UTC](https://community.zeek.org/t/strange-bro-build-problem-with-yacc-bison/1074 "2006-12-02T00:20:31Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@Stephen\_Lau1](https://community.zeek.org/u/Stephen_Lau1)
#### Post date: [December 2, 2006, 12:20am UTC](https://community.zeek.org/t/strange-bro-build-problem-with-yacc-bison/1074/1 "2006-12-02T00:20:31Z")
I attempted to compile Bro 1.2 on a FreeBSD 6.1 box with yacc installed
and Bro complained of the following:
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### Author:  [@Vern](https://community.zeek.org/u/Vern)
#### Post date: [December 2, 2006, 2:39am UTC](https://community.zeek.org/t/strange-bro-build-problem-with-yacc-bison/1074/2 "2006-12-02T02:39:55Z")
Yeah, we ran into this on a FreeBSD 6.1 machine too. It wasn't clear
at the time whether it was a general 6.1 problem or unique to our build;
I guess now we know :-).
I'm not sure what's the right autoconf goop to solve this - certainly
the current build failure isn't pretty.
Vern
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### Author:  [@Christian\_Kreibich3](https://community.zeek.org/u/Christian_Kreibich3)
#### Post date: [December 2, 2006, 8:33pm UTC](https://community.zeek.org/t/strange-bro-build-problem-with-yacc-bison/1074/3 "2006-12-02T20:33:17Z")
Such files should go into MOSTLYCLEANFILES. Try this:
Index: Makefile.am
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### Author:  [@system](https://community.zeek.org/u/system)
#### Post date: [May 6, 2022, 3:38pm UTC](https://community.zeek.org/t/strange-bro-build-problem-with-yacc-bison/1074/4 "2022-05-06T15:38:04Z")