Most likely the Sybase installation that is active when you build (i.e. pointed to by your $SYBASE env. variable) does NOT include this file.

This is usually the case when the default Sybase ASE install is a 64bit install - in that case you won't have all the necessary 32bit libraries (and in particular libblk.a will be missing).

So you need to have libblk.a in $SYBASE/$SYBASE_OCS/lib.

Michael