Fix regression in 2020.79 which prevented connecting with some SSH implementations. Increase MAX_PROPOSED_ALGO to 50, and print a log message if the limit is hit. This fixes interoperability with sshj library (used by PyCharm), and GoAnywhere. Reported by Pirmin Walthert and Piotr Jurkiewicz

Fix building with non-GCC compilers, reported by Kazuo Kuroi

Fix potential long delay in dbclient, found by OSS Fuzz

Fix null pointer dereference crash, found by OSS Fuzz

libtommath now uses the same random source as Dropbear (in 2020.79 and 2020.80 used getrandom() separately)

Some fuzzing improvements, start of a dbclient fuzzer