[CMake] How to test environment variable in IF command

[Mike Talbot]

Hi,

I'm trying to work out how to test for an environment variable in an IF 
command, the following doesn't work:

SET(ENV{FOO} ON)
MESSAGE("FOO = $ENV{FOO}")    # prints "FOO = ON"
IF(ENV{FOO})
  MESSAGE("FOO is set")
ENDIF(ENV{FOO})

Does anyone know what the right syntax for doing this is, please?

Thanks,
Mike

-- 
Mike Talbot
Core Petrel Architect (Abingdon)
Schlumberger
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