CMake: Do not include test targets in PCLConfig.cmake

[SergioRAgostinho]

Fixes #2429.

PCLConfig.cmake before the change

# ------------------------------------------------------------------------------------
# Helper to use PCL from outside project
#
# target_link_libraries(my_fabulous_target PCL_XXX_LIBRARIES) where XXX is the
# upper cased xxx from :
# 
# - common
# - kdtree
# - octree
# - search
# - tests_common
# - tests_kdtree
# - tests_octree
# - tests_search
#
# PCL_INCLUDE_DIRS is filled with PCL and available 3rdparty headers
# PCL_LIBRARY_DIRS is filled with PCL components libraries install directory and
# 3rdparty libraries paths
#
#                                   www.pointclouds.org
#------------------------------------------------------------------------------------

After the proposed patch

# ------------------------------------------------------------------------------------
# Helper to use PCL from outside project
#
# target_link_libraries(my_fabulous_target PCL_XXX_LIBRARIES) where XXX is the
# upper cased xxx from :
# 
# - common
# - kdtree
# - octree
# - search
#
# PCL_INCLUDE_DIRS is filled with PCL and available 3rdparty headers
# PCL_LIBRARY_DIRS is filled with PCL components libraries install directory and
# 3rdparty libraries paths
#
#                                   www.pointclouds.org
#------------------------------------------------------------------------------------

[taketwo]

Thanks, works for me. Though I needed to think a bit to understand the logic. Would something like this be more clear?

string(REGEX MATCH "^tests_" _is_test ${_ss})
if(_status AND NOT _is_test)
   ...

[SergioRAgostinho]

Your proposal is indeed much clearer and you get the feeling of what is happening just from looking at code. I changed it accordingly.