dont return a system path if cmake's 'WITH_INSTALL_PORTABLE' is enabled. this way...
-rw-r--r-- 37276 CMakeLists.txt
-rw-r--r-- 302 COPYING
-rw-r--r-- 2725 GNUmakefile
-rw-r--r-- 24846 SConstruct
drwxr-xr-x - build_files
drwxr-xr-x - doc
drwxr-xr-x - extern
drwxr-xr-x - intern
drwxr-xr-x - release
drwxr-xr-x - source