[cmake-developers] Cross compiling toolchain variables

[Brad King]

On 10/21/2013 04:23 PM, Stephen Kelly wrote:
> I have also not yet addressed the INSTALL_PREFIX issues here:
> 
>  http://thread.gmane.org/gmane.comp.programming.tools.cmake.devel/7292/focus=7373

This is the remaining issue not previously discussed in this thread.

> I think the mail from Samuel Martin does not change any significant facts 
> about the design. It seems from my reading that in his case, he would set 
> CMAKE_EXTERNAL_INSTALL_PREFIX.
> 
> Can I go ahead and investigate implementing what is described in the above 
> linked mail with CMAKE_EXTERNAL_INSTALL_PREFIX? Any updated ideas for a name 
> for the variable?

If I'm reading that thread correctly, the conclusion was the following
proposal:

- CMAKE_INSTALL_PREFIX will be set to the install prefix in which
  files will appear on the target device.  The path may not exist
  on the host anywhere.  Project code may use ${CMAKE_INSTALL_PREFIX}
  to generate and compile-in paths to be used at runtime on the
  target device.

- CMAKE_EXTERNAL_INSTALL_PREFIX can be set to a staging install prefix
  on the host.  This value will be used to set the default for
  CMAKE_INSTALL_PREFIX inside generated cmake_install.cmake files.
  The actual install rules will still use
  $ENV{DESTDIR}${CMAKE_INSTALL_PREFIX}, but the ${CMAKE_INSTALL_PREFIX}
  in this context will be the value of CMAKE_EXTERNAL_INSTALL_PREFIX.

In other words, the project is only aware of CMAKE_INSTALL_PREFIX at
configuration time, and CMAKE_EXTERNAL_INSTALL_PREFIX is used only at
"make install" time to stage target-destined files on the host.
How about the name "CMAKE_STAGING_PREFIX"?

-Brad