Build error on Debian 12 (OpenSSL 3.0.11): oid exists

[tbart]

The certificate generation step fails with more current openssl versions (likely 3.x+) with the following error:

make[1]: Entering directory '/mnt/scratch/metronome-master/certs'
openssl req -new -x509 -nodes -key localhost.key -days 1825 \
	-sha256 -out localhost.cert -utf8 -config localhost.cnf
problem creating object xmppAddr=1.3.6.1.5.5.7.8.5
40A750815F7F0000:error:04000066:object identifier routines:OBJ_create:oid exists:../crypto/objects/obj_dat.c:730:
make[1]: *** [Makefile:22: localhost.cert] Error 1
make[1]: Leaving directory '/mnt/scratch/metronome-master/certs'
make: *** [Makefile:20: all] Error 2

This seems to be due to the already configured OID in newer openssl versions.
It has an OID "XmppAddr" (note the capital X) in https://github.com/openssl/openssl/blob/master/crypto/objects/objects.txt already.

Sending a PR shortly.