用vc6编译snmp出错

snmpbulkget.obj : error LNK2001: unresolved external symbol _optarg
../bin/debug/snmpbulkget.exe : fatal error LNK1120: 1 unresolved externals

这就是错误的症状，我用的是net-snmp-5.4.2.1\net-snmp-5.4.2.1\win32下编译的，就是在编译snmpbulkget文件夹下面的内容时出的错，各位大侠们指点一下，谢谢了！

在编译snmpd文件夹下面的文件时出现的错误很多，
--------------------Configuration: snmpd - Win32 Debug--------------------
Linking...
snmpd.obj : error LNK2001: unresolved external symbol _optind
netsnmpmibs.lib(proxy.obj) : error LNK2001: unresolved external symbol _optind
snmpd.obj : error LNK2001: unresolved external symbol _optarg
netsnmpagent.lib(agent_trap.obj) : error LNK2001: unresolved external symbol _optarg
netsnmpmibs.lib(proxy.obj) : error LNK2001: unresolved external symbol _optarg
netsnmpmibs.lib(usmUser.obj) : error LNK2001: unresolved external symbol _usmHMACSHA1AuthProtocol
netsnmpmibs.lib(usmUser.obj) : error LNK2001: unresolved external symbol _usmHMACMD5AuthProtocol
netsnmpmibs.lib(usmUser.obj) : error LNK2001: unresolved external symbol _usmNoPrivProtocol
netsnmpmibs.lib(usmUser.obj) : error LNK2001: unresolved external symbol _usmNoAuthProtocol
netsnmpmibs.lib(usmUser.obj) : error LNK2001: unresolved external symbol _usmAESPrivProtocol
netsnmpmibs.lib(usmUser.obj) : error LNK2001: unresolved external symbol _usmDESPrivProtocol
../bin/debug/snmpd.exe : fatal error LNK1120: 8 unresolved externals
执行 link.exe 时出错.

snmpd.exe - 1 error(s), 0 warning(s)

哪位大哥帮帮忙，指点一下，感激不尽！