/var/log/messages has these:
Sep 22 16:29:40 hostname kernel: pid 42620 (zabbix_proxy), uid 122: exited on signal 11
So it get's SIGSEGV and dies.

Still cannot understand why this happenes, configured with
./configure --enable-proxy --with-mysql --without-libcurl --without-net-snmp

tried to compile and debugg with gdb, but with no sucsess.