Collabora Online moves out of The Document Foundation

They're not ignoring it. In addition to the terms of the GPL, libgcc code is covered by the GCC Runtime Library Exception[1], a form of dual-licensing, which states:

> You have permission to propagate a work of Target Code formed by combining the Runtime Library with Independent Modules, even if such propagation would otherwise violate the terms of GPLv3, provided that all Target Code was generated by Eligible Compilation Processes.

Which basically means that you can link libgcc with non-GPL code as long as no GPL-incompatible software was involved in the compilation process. (See the link for details.) The whole "Eligible Compilation Process" bit is intended to make things as difficult as possible for anyone wanting to use parts of GCC in combination with non-GPL external tools (separate programs generating or processing GCC IR, not linked with GCC), for example to use GCC as a backend for a proprietary compiler or to leverage GCC's parsers and IR optimization passes in front of a proprietary backend code generator. However, the only leverage they have for this is the trivial bit of C runtime code in libgcc, and so the added complexity and off-putting legal risk of the Runtime Library Exception all seems a bit pointless to me since anyone interested in doing such things could easily substitute an ABI-compatible runtime with a more permissive license, such as LLVM's libcompiler-rt. Or for that matter just use LLVM itself rather than GCC.

[1] https://www.gnu.org/licenses/gcc-exception-3.1.en.html