core generated when invoke mysql_init

[nishengzheng]

test.c is a mysql client for hpux11.11, and only invoke mysql api "mysql_init()";
when i combine it in this way, core will generated when execute.
gcc -o ./test test.c -I/usr/local/mysql/include -L /usr/local/mysql/lib -lmysqlclient -lpthread -lxti -lz -lm -lc -static
( if i remove the option -lpthread -static, it will work). so i think the problem is combine option.
How can I avoid this problem?

Thanks
Nishengzheng