Add dependency on Boost::align

[ecatmur]

it is required on Windows (from boost/asio/detail/memory.hpp), since MSVC doesn't have std::aligned_alloc

The source code in this repository is generated from an upstream repository at https://github.com/chriskohlhoff/asio.

Please consider raising new pull requests at https://github.com/chriskohlhoff/asio/pulls.

[Lastique]

This is also needed on Linux.

Ping @pdimov. Is CMakeLists.txt maintained locally by Boost? Looks like it's not part of the upstream ASIO.

[pdimov]

No idea who is maintaining the CML file. :-) The PR seems correct to me.

[pdimov]

But I can merge this if Chris wants us to maintain the CML. Chris?

[chriskohlhoff]

Commit applied.
Are there automated tests of this cmake stuff somewhere?

[pdimov]

There are some automated tests for Boost as a whole (whether it builds and installs with CMake), but they can't catch this. There are no outside tests that test every library one by one; such tests need to be enabled in the library repos.

Example workflows are this one that tests use with add_subdirectory and this one that tests use after installation.

[pdimov]

An easier approach for libraries such as Asio where CMakeLists.txt is generated by boostdep --cmake asio is to have a ci.yml job that compares the current contents to the generated output and fails if they don't match. Although this will occasionally fire when I make changes to boostdep.