Transform LAN_MIRROR into plain MIRROR:
- it does not have to be in the LAN
- offer mirror preference over upstream
- if selected, the mirror will be scanned before upstream servers
- if not selected, upstream servers will be scanned before the mirror
- I've set up such an internet-accessible mirror
- uClibc snapshot available
- MPFR releases available (the MPFR site is down from time to time)
- update all samples to use my mirror as a failover