If you are building 64-bit binaries, you must pass the define ODBC64. The example Application provides a demonstration of this. See the installed file example.txt for details.
You must also include the -xarch=v9 compiler switch if you are building 64-bit binaries. For instance, to build example, you would use:
CC -mt –DODBC64 -xarch=v9 -o example -I../include example.c -L../lib -lodbc –lCrun