As of cmake 2.6.0 targets must have globally unique names, or you get errors like this:
CMake Error at tools/build/CMake/BoostCore.cmake:1080 (add_executable):
add_executable cannot create target "test4" because another target with the
same name already exists. The existing target is an executable created in
source directory
"/home/troy/Projects/boost/branches/CMake/Boost_1_35_0/libs/variant/test".
See documentation for policy CMP0002 for more details.
Call Stack (most recent call first):
tools/build/CMake/BoostTesting.cmake:173 (boost_add_executable)
libs/xpressive/test/CMakeLists.txt:50 (boost_test_run)