Follow symlinks when uncompressing a file

[vishen]

When uncompressing a file, pacm should follow symlinks (only if that are inside the package) and write out the file. This is needed for nodejs which has the following:

$ ls -hal node-v10.16.0-linux-x64/bin/                                                                                             
total 40M
drwxr-xr-x 2 jonathan.pentecost jonathan.pentecost 4.0K Jul 13 10:07 ./
drwxr-xr-x 6 jonathan.pentecost jonathan.pentecost 4.0K Jul 13 10:07 ../
-rwxrwxr-x 1 jonathan.pentecost jonathan.pentecost  40M Jul 13 10:07 node*
lrwxrwxrwx 1 jonathan.pentecost jonathan.pentecost   38 Jul 13 10:07 npm -> ../lib/node_modules/npm/bin/npm-cli.js*
lrwxrwxrwx 1 jonathan.pentecost jonathan.pentecost   38 Jul 13 10:07 npx -> ../lib/node_modules/npm/bin/npx-cli.js*

So currently, only node is written to disk, the others are ignored. But npm and npx should both be written to disk (rather than symlinked).

[vishen]

This is actually more difficult than I first thought for node / npm. The node executable is a single binary so that is fine, but the npm and npx executables are javascript scripts, which rely on files from the included packages javascript files:

$ grep "require" ~/src/bin/npm 
  var unsupported = require('../lib/utils/unsupported.js')
  var log = require('npmlog')
  var npm = require('../lib/npm.js')
  var npmconf = require('../lib/config/core.js')
  var errorHandler = require('../lib/utils/error-handler.js')
  var nopt = require('nopt')
      const pkg = require('../package.json')
      let notifier = require('update-notifier')({pkg})
      const isCI = require('ci-info').isCI
        const color = require('ansicolors')

It might be time to look at extracting the code related to a package, have created a new issue for that #7.