[RFC]: Add C implementation for `@stdlib/math/base/special/sici`

[Deepak91168]

Description

This RFC proposes adding C implementation for @stdlib/math/base/special/sici.

double stdlib_base_sici( const double x );

Related Issues

Related issues #649

Questions

No.

Other

No.

Checklist

• I have read and understood the Code of Conduct.
• Searched for existing issues and pull requests.
• The issue name begins with RFC:.

[deepak427]

Is anyone working on this issue or has anyone opened a PR to resolve it? Please let me know.

[schnrj]

@deepak427 Yeah, i am working on this .