stderr of server threads swallowed during integration tests about dqlite HOT 2 OPEN

This might have something to do with integration tests inadvertently linking to an installed libdqlite instead of the just-built one, since I was able to "fix" it by blowing away the lib directory where those artifacts were installed. A good sanity check is to replace the definition of tracef by

#define tracef(...) do { \
		if (UNLIKELY(_dqliteTracingEnabled)) { \
			__builtin_trap(); \
		} \
	} while (0)

from dqlite.

I wonder if the _dqliteTracingEnabled static is getting duplicated somehow.

from dqlite.