[FR] Separated amalgamation header file for C API, or wrap the C++/C sections in an ifdef

[oviano]

I have written a Botan-based crypto service provider for the SRT library:

Haivision/srt#2700

While looking at how to integrate Botan into the SRT CMake build system, I came across this:

https://github.com/Tectu/botan-cmake

This seems like a potential solution but since the SRT crypto framework is written in C, it requires the FFI Botan interface. However, the Botan amalgamation build includes everything in botan_all.h, which cannot be included in SRT because it contains a bunch of C++ classes etc.

So my suggestions are:

1. Split "botan_all.h" into "botan_all_cpp.h" and "botan_all_c.h". Or maybe just leave botan_all.h as it is, but include "botan_all_ffi.h" containing just the FFI subset.

OR

2. Wrap the C++ and C sections of the "botan_all.h" file in ifdefs that can then be defined prior to including "botan_all.h".

OR

Another solution?

[randombit]

Yeah good point. Probably we want to leave botan_all.h as it is and create a new FFI-specific header for anyone only using the C interface.

[oviano]

For now it seems that the three files ffi.h build.h and compiler.h are all that are required, but it would be good to reduce that to a single file!

I did have a look at the configure script but it was quite complex.