contrib/libxo: fix API header files inclusions in C++ source files

[khng]

Summary

C++ source files need extern "C" to disable C++ name mangling.

[khng]

@phil for a confirmation as well.

[phil]

Patch looks fine. I'll add to the main libxo repo.

Thanks,
Phil

[lwhsu]

In D47930#1093223, @phil wrote:

Patch looks fine. I'll add to the main libxo repo.

Thanks,
Phil

FYI @aokblast also submitted as https://github.com/Juniper/libxo/pull/100

[aokblast]

Update with github version

[imp]

Looks good, not surprised upstream accepted it :).

[phil]

Why do you need this on xo_buf.h, an internal file?

In the FWIW department: It always seems odd that C++ needs decoration in non-C++ files, rather that have this knowledge in compiler command line arguments (e.g. "--c-include /usr/include").

Thanks,
Phil

[aokblast]

In D47930#1191301, @phil wrote:

Why do you need this on xo_buf.h, an internal file?

In the FWIW department: It always seems odd that C++ needs decoration in non-C++ files, rather that have this knowledge in compiler command line arguments (e.g. "--c-include /usr/include").

Thanks,
Phil

Oops sorry. @khng tells me that he will figure it out before merging it.

[khng]

Updated.

[phil]

Looks good. Thanks..