Added KPHP compiler

[Danil42Russia]

Features

• KPHP analyzes your code as a whole and performs various optimizations focusing on performance and safety.
• Inferring types of all variables, how to declare them in C++.
• Compile-time optimizations, such as inlining getters or reducing refcounters flapping.
• Compile-time checks, including immutability and type system requirements.
• Runtime optimizations, like constant arrays pre-initing and typed vectors.
• KPHP has coroutines.
• Support for PHP 7.4 features (PHP 8.0, 8.1 features already implemented and underway)
• Translates 8 million lines of code in 50 seconds.

Other

Used for more than 10 years in a real project under high load.

[spekulatius]

Nice, looks like a great addition!