Support building when package is not in the root directory

[asgrim]

From @zeriyoshi - original proposal in #82

Add extension-src directive to the php-ext section in composer.json.

This enables support for patterns where extension source code is not located in the project root, which is commonly seen in third-party extensions.

https://github.com/protocolbuffers/protobuf/tree/main/php/ext/google/protobuf

{
    "name": "google/protobuf",
    "type": "php-ext",
    "description": "protocolbuffers php extension",
    "php-ext": {
        "extension-name": "protobuf",
        "extension-src": "php/ext/google/protobuf"
    }
}

Investigate options, check this makes sense and is clear. Documentation would be needed, and upstream Composer schema support.

[asgrim]

I will revisit this after #83 is merged

[macintoshplus]

@asgrim This option can specify the name of the extension DLL?

Other automated scripts already use the zip attached on the GitHub release to install an extension automatically. It's hard to change the dll name into the zip archive without breaking something.

[asgrim]

@asgrim This option can specify the name of the extension DLL?

Other automated scripts already use the zip attached on the GitHub release to install an extension automatically. It's hard to change the dll name into the zip archive without breaking something.

This is an entirely separate issue

[asgrim]

@zeriyoshi I gave this some thought, I think build-path may be a better name for this.

https://github.com/ThePHPF/pie-design/pull/28

If there is no further feedback, please leave it with me, I have a PR updated and also will send a patch upstream to Composer.