current CAPI of CompilerEngine isn't really a CAPI. It's initial need
was for the python bindings to have access to the CompilerEngine through
a convenient API. So we now make a clear separation of CAPI and python
wrappers. So we now have wrappers functions, that can be implemented
using C/C++, and will be exposed to python via pybind11. And we have a
CAPI (still need fixing as it still contains C++ code), that can be used
as is, or to build bindings for other languages (such as Rust).
this required to have a CAPI that when asked for types, returns a
structure that can report if an error was faced during type creation.
This is required since a failure at that stage in the compiler would
lead to a segfault in the python bindings for example, and we want to be
able to handle this scenario gracefully.
Quick fix due to ordering of includes, had to add #include
<mlir/Transforms/DialectConversion.h> to include/concretelang/Conversion/Utils/GenericOpTypeConversionPattern.h
