[cmake-developers] output expressions fails with either a build.ninja error or wrong escaped space

[Brad King]

On 05/28/2016 01:15 PM, jerry.c.t at web.de wrote:
>   "-I$<JOIN:$<TARGET_PROPERTY:dummy,INCLUDE_DIRECTORIES>, -I>"

This tells CMake to generate a single argument consisting of the
entire expanded value.  We have no syntax to expand lists into
multiple command line arguments after evaluation of generator
expressions.  Without the quotes the "$<" and ">" parts appear
in different arguments to add_custom_command and so it is not
recognized as a generator expression.

It is not currently possible to do what you are trying to do.
You'll need to use file(GENERATE) to produce a script holding
the desired command instead.  Then launch the script as the
custom target's command.

-Brad