Make dudect ready for C++

[FAlbertDev]

• Rename variables named class into clazz
• Add explicit casts for calloc
• Remove spaces at line end (not C++ relevant)

[oreparaz]

Thanks. I'm positive about this. Two questions:

• Shouldn't we include the extern "C" {...} logic around this (possibly guarded by __cplusplus)? Something like https://isocpp.org/wiki/faq/mixing-c-and-cpp#include-c-hdrs-personal
• Did you test this? how?

[FAlbertDev]

Shouldn't we include the extern "C" {...} logic around this (possibly guarded by __cplusplus)?

Sure! I did't know about this. (added in d9241fe)

Did you test this? how?

I used the following CMake example project, using the dudect.h header:
dudect_cpp_example.zip

Build and execute:
cmake . && make && ./dudect_example

[oreparaz]

Thanks! Merging...