If you have Microsoft Visual C++ installed on your computer, Windows Services for UNIX setup will configure the Interix Software Development Kit (SDK) to work with Visual C++.
If you install Microsoft Visual C++ after you have installed, the Interix SDK, you must provide the location of the Visual C++ compiler and linker to the cc(1) and c89(1) utilities. To do this, you must use the Windows System Properties dialog box to create a Windows system variable named INTERIX_COMPILERDIR and set its value to the path of the directory in which you installed Visual C++, in POSIX format. For example, if you installed Visual C++ in the directory C:\MSDEV, the value of INTERIX_COMPILERDIR would be /dev/fs/C/MSDEV. If the path contains spaces, be sure to use the 8.3 version of the path; for more information, see Spaces within directory names. For information about using the System Properties dialog box to set system variables, see Windows Help.