src:glm/0.9.9~a2-1 triggered FTBFS for src:forge and src:gli

[Ghislain Vaillant <ghisvail@gmail.com>]

Dear Guus,

I would have appreciated to be notified of the recent upload of
src:glm/0.9.9~a2-1 **straight to unstable** despite the library
breaking the build for two of its rdepends: src:forge (#888931) and
src:gli (#888933).

This situation could have been easily avoided with better communication
and a short trip to experimental.

Ghis