docs: add missing prerequisites: brotli, boost, libseccomp

[veprbl]

The list of prerequisites is incomplete. This should add the missing ones. The minimal supported version of "boost" is determined by trying different versions until nix compiled successfully.

This would need a backport to the maintenance branch.

Fixes: #2568

[endgame]

Great work. If you want to be specific about which parts of boost nix needs to build, it's only the context library, everything else is header-only. (build boost with --wtih-libraries=context).

[endgame]

I didn't realise this was optional. I just assumed it was required because configure bombs out if you don't have it.

[veprbl]

@endgame
For me, it builds with boost that was built --with-libraries="", so it seems like context2 library is header-only. I don't think it's worth to go to such details and describe this in the manual because this might get outdated because of the changes either in nix or in boost.

[endgame]

Interesting. I had a link failure on aarch64. I agree with your point, regardless.

[veprbl]

@endgame Can you try my script https://gitlab.com/veprbl/nix-bootstrap/blob/master/bootstrap.sh ?

[endgame]

Strange. AFAICT it's unconditionally linking against -lboost_context at

nix/src/libutil/local.mk

Line 9 in 6924bdf

libutil_LDFLAGS = $(LIBLZMA_LIBS) -lbz2 -pthread $(OPENSSL_LIBS) $(LIBBROTLI_LIBS) -lboost_context

Do you want that script run on amd64 or aarch64?

[veprbl]

@endgame
I found this line too, but somehow that didn't look suspicious to me at the time. Turns out --with-libraries="" builds all boost libraries... So this is why my build didn't fail. I poked it a bit more and it seems like the minimal working boost configuration currently is --with-libraries=context.

[edolstra]

I believe it should be higher due to some boost::coroutine2 bug in previous releases. Maybe 1.65 but I'm not sure.

[veprbl]

@edolstra
I guess you are referring to

nix/src/libutil/serialise.cc

Lines 160 to 162 in 03ce0c3

	#if BOOST_VERSION >= 106300 && BOOST_VERSION < 106600
	#error Coroutines are broken in this version of Boost!
	#endif

It singles out 1.63.x, 1.64.x, 1.65.x to exclude specifically. A test can be done a following way:

with import <nixpkgs> {};

map (boost: nix.override { inherit boost; })
[
  #boost155
  #boost159
  #boost160 ld: symbol(s) not found for architecture x86_64
  #boost161 not in nixpkgs, but works if you add it
  boost162
  #boost163 assert fails in serialise.cc
  #boost164 assert fails in serialise.cc
  #boost165 assert fails in serialise.cc
  boost166
  boost167
  boost168
]

All four build for me (including installCheckPhase) just fine. I can change the minimum version to 1.66, if you think that is needed.

[edolstra]

Thanks for investigating :-)

[endgame]

@veprbl Well, that explains it. Do you still need me to run that script, and if so, on which arch?

[veprbl]

@endgame I think we are good. You were right about boost_context being a dependency, thanks for pointing that out. Also I learn that coroutine2 used to be a shared library in older versions of boost.