Comment 24 for bug 57921

I've seen this problem to be open quite long time, and I believe it occurs
because exim tries to generate Diffie Hellman parameters on the fly when they
don't exist. This situation may occur when the gnutls-params file is missing.
I propose some solutions.

1. Return an error if the gnutls-params file does not exist. (sol1.patch)

2. Generate the parameters in a non-blocking way using /dev/urandom.
(sol2.patch)

3. Read static parameters if the file does not exist.

I believe the third solution is the most elegant. Generating these parameters
on the fly (sol2) even if /dev/urandom is used is time consuming and not
really appropriate for a server. The idea is to have them pregenerated.

Using static parameters (sol3) does not harm in any way.
If somebody wants different ones he can generate them.

So the