Description of problem:

In build settings of an autotools project, variables in user defined options are
expanded in the overall preview, but not when invoking configure from the
command line.

Version-Release number of selected component (if applicable):

autotools-0.9.5, cdt-4.0.1, eclipse-3.4M2

How reproducible:

Always.

Steps to Reproduce:
1. In configure settings, in user-specified configuration options enter a
variable expression like --x-includes=${workspace_loc:/project_name/include}
2. Build.
  
Actual results:

The variable will appear correctly expanded in the "All options" preview line,
but when building, the variable will not be expanded, and the option passed
literally, and configure will fail.

Expected results:

The variable should be also expanded when invoking configure.

Additional info:

The workaround is to write options, absolute paths, etc. by hand. Which is time
consuming, and will break if the workspace/project is moved.