Add c++ linking example

[thibaultbarbie]

I added an example for the compilation and linking of a bundled C++ library (#296).

[j-haj]

Overall I think this looks really good! Great work! I only have one nitpick on wording..

[j-haj]

Just a few nitpicks here. I think there is room to improve the clarity of these sentences.

Linking a bundled C++ library is almost the same as linking it with a C library.

I would reword this. I understand what you are saying here, but the use of "it" here technically refers to the bundled C++ library, although it seems you are using it to refer to the compiled binary. Something along the lines of "Linking a bundled C++ library is very similar to linking a bundled C library."

The main difference is the [cpp][cc-build-cpp] option that should be put to true and the addition of extern "C" in the foo.cpp file.

I would reword this as well. cpp(true) is a method used as part of the Builder pattern, not technically an option. I would reword to something along these lines:

"The two core differences when compiling and statically linking a bundled C++ library are specifying a C++ compiler via the builder method cpp(true) and preventing name mangling by the C++ compiler by adding the extern "C" section at the top of our C++ source file.

[thibaultbarbie]

Thanks for your suggestion! I agree it is a far better explanation now.

[budziq]

Nicely done @thibaultbarbie !

Thanks for the great help @j-haj !