The previous report was done after noticing a lot more of problems when using the stack glfw3 + glm + epoxy + mesa with intel drivers. Valgrind reports lot of memory problems notably when using glCompileShader, when loading shared libraries (dlopen) and many more. I can provide the source code that I'm writing which triggers those, it's intended to be FOSS in any case, but it's very young and does nothing interesting (taking my time to write code with every possible error checking in the graphical stack).
I have not reported those information is original bug report, because they do not belong directly to glfw3. Sending multiple reports would be an option, but I'm not sure it's very productive, especially if this is going to be ignored (problems are only seen with valgrind AFAIK and some of those might be related to stuff I did in my code, notably the shaders. I need to dig more to be confident enough there to send a report.)