[p7zip_jll] Set LIBPATH and LIBPATH_list at init-time

[giordano]

Fix #39154, take 2 (or 3?). Ref: docker-library/julia#51 (comment)

Should be backported to release-1.6

[giordano]

As far as I could see, most JLLs do something like

julia/stdlib/LibGit2_jll/src/LibGit2_jll.jl

Lines 33 to 34 in 5d7e13f

	LIBPATH[] = dirname(libgit2_path)
	push!(LIBPATH_list, LIBPATH[])

because they're libraries, and only need to add to the libpath the directory they're in. However, 7zip is in a different directory, the best I could do was to try both joinpath(Sys.BINDIR, Base.LIBDIR, "julia") and joinpath(Sys.BINDIR, Base.LIBDIR), is there a better way to find the directory where libstdc++ is?

[fredrikekre]

tester_linux64:

ERROR: LoadError: On worker 23:
UndefRefError: access to undefined reference
Stacktrace:
 [1] getproperty
   @ ./Base.jl:33
 [2] #447
   @ /buildworker/worker/tester_linux64/build/share/julia/stdlib/v1.7/Distributed/test/distributed_exec.jl:1607
 [3] #106
   @ /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.7/Distributed/src/process_messages.jl:278
 [4] run_work_thunk
   @ /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.7/Distributed/src/process_messages.jl:63
 [5] macro expansion
   @ /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.7/Distributed/src/process_messages.jl:278 [inlined]
 [6] #105
   @ ./task.jl:406
Stacktrace:
 [1] (::Base.var"#876#878")(x::Task)
   @ Base ./asyncmap.jl:177
 [2] foreach(f::Base.var"#876#878", itr::Vector{Any})
   @ Base ./abstractarray.jl:2146
 [3] maptwice(wrapped_f::Function, chnl::Channel{Any}, worker_tasks::Vector{Any}, c::Vector{Int64})
   @ Base ./asyncmap.jl:177
 [4] wrap_n_exec_twice
   @ ./asyncmap.jl:153 [inlined]
 [5] async_usemap(f::var"#446#448", c::Vector{Int64}; ntasks::Int64, batch_size::Nothing)
   @ Base ./asyncmap.jl:103
 [6] #asyncmap#860
   @ ./asyncmap.jl:81 [inlined]
 [7] asyncmap
   @ ./asyncmap.jl:81 [inlined]
 [8] reuseport_tests()
   @ Main /buildworker/worker/tester_linux64/build/share/julia/stdlib/v1.7/Distributed/test/distributed_exec.jl:1601
 [9] top-level scope
   @ /buildworker/worker/tester_linux64/build/share/julia/stdlib/v1.7/Distributed/test/distributed_exec.jl:1637
in expression starting at /buildworker/worker/tester_linux64/build/share/julia/stdlib/v1.7/Distributed/test/distributed_exec.jl:1636

Is there an open issue about this? Logs: https://build.julialang.org/#/builders/71/builds/566/steps/5/logs/stdio