Resolve custom vendor directories for relative patch files

[Caffe1neAdd1ct]

I'm using a repo with patches contained inside pulled in via this patching plugin for composer:

https://github.com/zVPS/laravel-patches/blob/v4.2.22/composer.json

When installing via composer and a custom directory e.g /vendor-install via COMPOSER_VENDOR_DIR= I get an error as the patches need to be relative to the project root.

This pull request adds the functionality to check for vendor/ paths and translate to COMPOSER_VENDOR_DIR if specified.

[Caffe1neAdd1ct]

Raised with composer and the view is to fix this here not in composer.

https://github.com/composer/composer/issues/8035

[stof]

note that the vendor dir can also be customized through the config, not only from the env variable.

[Caffe1neAdd1ct]

Thanks @stof

Quick example for reference:

{
    "config": {
        "vendor-dir": "vendor-install"
    }
}

[CybotTM]

Closing due to being abandoned.