how to build the lmgrypt.exe with the flexlm SDK?

I downloaded the flexlm SDK v8.1 & v9.2.

I builded lmgrypt.c with microsoft viusal C++ 6.0, include the necessary head file(.h) and linked to lmgr8b.lib.

after builded it i got an error:

--------------------Configuration: lmcrypt - Win32 Debug--------------------
Linking...
lmcrypt.obj : error LNK2001: unresolved external symbol _l_prikey_sign
Debug/lmcrypt.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.

lmcrypt.exe - 2 error(s), 0 warning(s)


where is the function _l_prikey_sign?