If you are building 64-bit binaries, you must pass the define ODBC64. The example Application provides a demonstration of this. Refer to the installed file example.txt for details.

You must also include the correct compiler switches if you are building 64-bit binaries. For instance, to build example, you would use: 

g++ -o example -DODBC64 -I../include example.c -L../lib -lodbc -lodbcinst -lc