Error "fatal error C1034: windows.h: no include path set"

OS Windows Vista Ultimate

I am trying to run a program called minimal.c. When I type at the command line:

C:\Users\nathan\Desktop>cl minimal.c
Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 14.00.50727.762 for 80x86

Copyright (C) Microsoft Corporation.  All rights reserved.

minimal.c
minimal.c(5) : fatal error C1034: windows.h: no include path set

I have set all the paths:

C:\Users\nathan\Desktop>path
PATH=C:\Program Files (x86)\Microsoft Visual Studio 8\VC\bin;C:\Windows\system3
;C:\Windows;C:\Windows\System32\Wbem;C:\Program Files (x86)\ATI Technologies\AT
.ACE\Core-Static;C:\Program Files\Intel\DMIX;c:\Program Files (x86)\Microsoft S
L Server\100\Tools\Binn\;c:\Program Files (x86)\Microsoft SQL Server\100\DTS\Bi
n\;C:\Program Files (x86)\QuickTime\QTSystem\;C:\Program Files (x86)\Java\jdk1.
.0_13\bin;C:\Program Files (x86)\Autodesk\Backburner\;C:\Program Files (x86)\Co
mon Files\Autodesk Shared\;C:\Program Files (x86)\Microsoft DirectX SDK (March
009)\Include;C:\Users\nathan\Desktop\glut-3.7.6-bin\glut-3.7.6-bin;C:\Program F
les (x86)\Microsoft Visual Studio 8\Common7\IDE;C:\Program Files (x86)\Microsof
 Visual Studio 8\VC\PlatformSDK\Include;C:\Program Files (x86)\Microsoft Visual
Studio 8\VC\PlatformSDK\Include\gl

I have gone and made sure windows.h is in the directory. I'm setting the path too. It's in C:\Program Files (x86)\Microsoft Visual Studio 8\VC\PlatformSDK\Include.

I have Visual Studio 2005.

I have exhausted all possibilities. Any ideas?

You could also run the vcvars32.bat file from the directory C:\Program Files\Microsoft Visual Studio 8\VC\bin (this is in your path) prior to your cl command.

Like this:

C:\Users\nathan\Desktop>vcvars32
C:\Users\nathan\Desktop>cl minimal.c

vcvars32 calls C:\Program Files\Microsoft Visual Studio 8\Common7\Tools\vsvars32.bat which sets up the required environment for compiling and linking.

The environment variables are INCLUDE, LIB, and PATH.

The compiler looks for header files in the INCLUDE path during compile, and libraries are fetched from the LIB path during link.

For me, with Visual Studio 2017,

"C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\Tools\vsdevcmd.bat"

is the command to use before compiling with cl.

Here is the documentation.