dlopen/dlcose change

[daviehh]

Related: #396

also reported JuliaGraphics/Cairo.jl#271 and JuliaLang/julia#31517

According to the glib upstream https://gitlab.gnome.org/GNOME/pango/issues/363, dlopen followed by dlclose is not supported and it's surprising if it worked before.

Should changes be made to BinDeps.jl?

• do not use dlclose() at all: maybe using h = nothing instead (is it safe? shall we also use GC.gc()?)

  BinDeps.jl/src/dependencies.jl

  Line 681 in f375ead

  Libdl.dlclose(h)

• or, test if file exist at path; is so, use addprocs() and remotecall() , then rmprocs() to execute in new process each time?

[cormullion]

Isn't BinDeps obsolescent?

The old world of BinDeps.jl fades slowly into the long, dark sleep of forgotten heroes.

Elliot in 2018

[jonathanBieler]

BinDeps is still used by a lot of packages, it needs to be maintained, at least for a while.

It looks like the build command is ran in a separate process, so maybe not closing the libraries isn't an issue. We could try it out.

[daviehh]

@jonathanBieler not closing libraries for cairo by using: daviehh/Cairo.jl@1f59845

• doesn't segfault for julia 0.7 and 1.0 (CI error for julia v0.6 since pathof not available there):
  https://travis-ci.org/daviehh/Cairo.jl/builds/515349602

• not sure how "safe" it would be: like you mentioned, many other packages use it; but it runs on a separate process so may be the impact is low.

• btw, upstream glib thinks dlopen/dlclose is not supported to be used that way and may not fix it:
  https://gitlab.gnome.org/GNOME/pango/issues/363