Tests: Add coverage for special characters in include directories
We have tests for special characters in preprocessor definitions and
custom command line arguments. Add such a test for include directories.
Currently the Makefiles generators do not escape paths in depend.make
in all cases, so leave a FIXME comment and skip the test for those.
Also fix the Xcode generator to quote paths containing [ or ] but not a space.
That makes the new test pass with or without spaces in the path to the CMake
build tree. Local testing shows that the quoting is not needed for the other
special characters.
Issue: #20555 (closed)