create libyaml_vendor

[mikaelarguedas]

This adds a vendor package that clones and build the libyaml 1.8.0rc.
This is the first version of libyaml providing a CMake module but the release is not tagged/released yet

Required by ros2/ros2#491 and ros2/rcl#235

Connects to ros2/rcl#235

[mikaelarguedas]

• Linux
• Linux-aarch64
• macOS
• Windows

[mikaelarguedas]

This cannot be merged as is as libyaml_vendor doesnt generate/install yaml.lib ATM: ros2/rcl#235 (comment)

[sloretz]

I wasn't able to locally reproduce the issue of yaml.lib not getting installed on windows using --merge-install. Running windows CI to see if there is a difference

Repos file uses this branch + rcl branch yaml_param_parser_shane_review_2

[mikaelarguedas]

I wasn't able to locally reproduce the issue of yaml.lib not getting installed on windows using --merge-install.

This issue has been fixed by fiddling with the way we pass cmake args to the external project.

The remaining issue is the that Fast-RTPS fails to build if libyaml_vendor build started before Fast-RTPS's (happens only on windows, in a merged install space).

I ran another job with your repos file to reproduce the issue

[sloretz]

@mikaelarguedas re-running the job from your comment with b3d4bf7.

libyaml creates and installs a file config.h. Fast-RTPS generates a file of the same name that defines HAVE_SECURITY. When doing a --merge-install the compiler found the one in the install space before the build space, which meant HAVE_SECURITY wasn't defined when building SecurityManager.cpp

[mikaelarguedas]

Thanks @sloretz for looking into it.

the compiler found the one in the install space before the build space

This looks like an include path order issue to me.

It's a bit odd though that Fast-RTPS relies on it's own generated config.h file at build/link time as I would expect this file to be made for and used by downstream packages exclusively.

As we rely on the Fast-RTPS config file to be available in the install space when building other packages such as rmw_fastrtps_cpp this seems to bee the right temporary fix to me 👍.

Though we should report it to eProsima as this seems more of a hack that a proper solution. The install location do not collide as the files are installed to different subdirectories. Do you agree?

[sloretz]

This looks like an include path order issue to me

Sort of. I don't think we have control of when system headers are searched. As far as I can tell this can't be specified in cmake (ex: there are no calls to target_include_directories(tgt /usr/include)). I opened an issue to use the project name in the build space include path eProsima/Fast-DDS#221

Though we should report it to eProsima as this seems more of a hack that a proper solution

I'm happy with this fix long term. libyaml installing a file as generic as <config.h> seems like the real issue to me.

The install location do not collide as the files are installed to different subdirectories. Do you agree?

Correct there is no collision. Fast-RTPS installs <fastrtps/config.h>, where libyaml installs <config.h>