Set C++ 11

[moriarty]

Because @lucbettaieb said he got an email about:

http://build.ros.org/job/Ldev__sparse_bundle_adjustment__ubuntu_xenial_amd64/3/

@mikeferguson I also added myself as a maintainer. I'm taking care of whatever the fetch_ros packages depend on.

[mikeferguson]

2 things:

• I don't think we want to do it this way. Melodic will pass in a build format of C++14 when building debs -- so I think we want to set C++11 ONLY if no build version is set (otherwise we might end up with weird linking errors on Melodic, where everything else is built in C++14).
• If you're taking over for Luc, should we remove him from the list of maintainers?

[mikeferguson]

Disregard my first comment -- looks like roscpp is hard coding C++11 -- so I guess we'll be OK.

Second comment remains.

[lucbettaieb]

I don't mind getting the emails, etc, so I'm happy to stay on. Otherwise, I don't mind.

[mikeferguson]

Ok -- I'll let that run through CI -- if it passes on Melodic and Lunar, I'll cut a new release. (I think we should also switch slam_karto to melodic-devel branch for Lunar once this is released)(

[dirk-thomas]

The CMake recommended way is now:

if(NOT CMAKE_CXX_STANDARD)
  set(CMAKE_CXX_STANDARD 11)
endif()

This works cross platform and allows to override it if necessary.

[moriarty]

Ah I thought I remembered seeing a recommended way...
I just checked tf and went with the way it was done there.

[mikeferguson]

Thanks @dirk-thomas -- I'll update to that

[mikeferguson]

One note for posterity: CMAKE_CXX_STANDARD requires CMAKE > 3.1, so old CMakeLists needs to be updated to have new minimum version

[dirk-thomas]

CMake >= 3.1 😉

[mikeferguson]

0.4.2 is out for lunar, coming for melodic momentarily