`NIMBLE_DIR=$HOME/.nimble_alt nimble install pkgname` doesn't work unless i also add `XDG_CONFIG_HOME= `
fails:
```
NIMBLE_DIR=$HOME/.nimble_fake65b nimble install jester
   Warning: Using the environment variable: NIMBLE_DIR='/Users/timothee/.nimble_fake65b'
    Prompt: No local packages.json found, download it from internet? [y/N]
    Answer: y
Downloading official package list
    Success Package list downloaded.
Downloading https://github.com/dom96/jester using git
  Verifying dependencies for jester@0.5.0
 Installing httpbeast@>= 0.2.2
    Prompt: httpbeast not found in any local packages.json, check internet for updated packages? [y/N]
    Answer: y
Downloading official package list
    Success Package list downloaded.
       Tip: 19 messages have been suppressed, use --verbose to show them.
     Error: Package not found.
```
works, if i also add `XDG_CONFIG_HOME= `
```
NIMBLE_DIR=$HOME/.nimble_fake65 XDG_CONFIG_HOME= nimble install jester
   Warning: Using the environment variable: NIMBLE_DIR='/Users/timothee/.nimble_fake65'
    Prompt: No local packages.json found, download it from internet? [y/N]
    Answer: y
Downloading Official package list
    Success Package list downloaded.
Downloading https://github.com/dom96/jester using git
  Verifying dependencies for jester@0.5.0
 Installing httpbeast@>= 0.2.2
Downloading https://github.com/dom96/httpbeast using git
  Verifying dependencies for httpbeast@0.3.0
 Installing https://github.com/iffy/asynctools@#pr_fix_for_latest
Downloading https://github.com/iffy/asynctools using git
  Verifying dependencies for asynctools@#pr_fix_for_latest
 Installing asynctools@#pr_fix_for_latest
   Success: asynctools installed successfully.
 Installing httpbeast@0.3.0
   Success: httpbeast installed successfully.
 Installing https://github.com/timotheecour/asynctools@#pr_fix_compilation
Downloading https://github.com/timotheecour/asynctools using git
  Verifying dependencies for asynctools@#pr_fix_compilation
 Installing asynctools@#pr_fix_compilation
   Success: asynctools installed successfully.
 Installing jester@0.5.0
   Success: jester installed successfully.
```