cmake install with relative path fails

Created by: dpugmire

make install will fail if I use an install dir with a relative path in it.

For instance: I have a build and install dir that are in the same subdir.

cmake -DCMAKE_INSTALL_PREFIX=../install SRC-DIR

make will be fine, but make install will fail.

(sorry i put the wrong command in... this is an edit. I did use the cmake_install_previx)