rework Conda structure

Author: t-bltg

docs/ci_build.sh

@@ -56,21 +56,20 @@ $julia -e '
   Pkg.add("Conda"); Pkg.build("Conda"; verbose=true)
   using Conda; env, rc = Conda.ROOTENV, Conda.conda_rc(Conda.ROOTENV)
   Conda.runconda(`config --set auto_update_conda False --file $rc --force`, env)
-  Pkg.add("PyCall"); Pkg.build("PyCall"; verbose=true)
   if Sys.islinux()
     # see discourse.julialang.org/t/glibcxx-version-not-found/82209/8
     # julia 1.8.3 is built with libstdc++.so.6.0.29, so we must restrict to this version (gcc 11.3.0, not gcc 12.2.0)
-    libstdcxx_ver = Base.BinaryPlatforms.detect_libstdcxx_version()
     gcc_major = Dict(
       v"3.4.29" => 11,
       v"3.4.30" => 12,
       # ... keep this up-to-date with gcc 13
-    )[libstdcxx_ver]
+    )[Base.BinaryPlatforms.detect_libstdcxx_version()]
     Conda.add("libgcc-ng=$gcc_major")
     Conda.add("libstdcxx-ng=$gcc_major")
   end
   Conda.add("matplotlib")
   Conda.list()
+  Pkg.add("PyCall"); Pkg.build("PyCall"; verbose=true)
 '
 
 # tentative fix for `pyplot` bug: libstdc++.so.X: version `GLIBCXX_X.X.X' not found ...