Set interface compile features to cxx_std_14 on PCL targets

For CMake older than 3.8 fall back to using cxx_attribute_deprecated
since the former did not exist yet.

CMakeLists.txt

@@ -7,10 +7,17 @@ if(POLICY CMP0074)
   cmake_policy(SET CMP0074 NEW)
 endif()
 
-# Set target C++ standard
+# Set target C++ standard and required compiler features
 set(CMAKE_CXX_STANDARD 14 CACHE STRING "The target C++ standard. PCL requires C++14 or higher.")
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
+if(CMAKE_VERSION VERSION_LESS 3.8)
+  # CMake did not have cxx_std_14 compile feature prior to 3.8
+  # We use cxx_attribute_deprecated as a proxy because this feature is a part of c++14 standard
+  set(PCL_CXX_COMPILE_FEATURES cxx_attribute_deprecated)
+else()
+  set(PCL_CXX_COMPILE_FEATURES cxx_std_14)
+endif()
 
 set(CMAKE_CONFIGURATION_TYPES "Debug;Release" CACHE STRING "possible configurations" FORCE)
 

PCLConfig.cmake.in

@@ -613,6 +613,7 @@ foreach(component ${PCL_TO_FIND_COMPONENTS})
           PROPERTIES
             INTERFACE_COMPILE_DEFINITIONS "${definitions}"
             INTERFACE_COMPILE_OPTIONS "${PCL_COMPILE_OPTIONS}"
+            INTERFACE_COMPILE_FEATURES "@PCL_CXX_COMPILE_FEATURES@"
             INTERFACE_INCLUDE_DIRECTORIES "${PCL_${COMPONENT}_INCLUDE_DIRS}"
             INTERFACE_LINK_LIBRARIES "${PCL_${COMPONENT}_LINK_LIBRARIES}"
         )
@@ -621,6 +622,7 @@ foreach(component ${PCL_TO_FIND_COMPONENTS})
           PROPERTIES
             INTERFACE_COMPILE_DEFINITIONS "${definitions}"
             INTERFACE_COMPILE_OPTIONS "$<$<COMPILE_LANGUAGE:CXX>:${PCL_COMPILE_OPTIONS}>"
+            INTERFACE_COMPILE_FEATURES "@PCL_CXX_COMPILE_FEATURES@"
             INTERFACE_INCLUDE_DIRECTORIES "${PCL_${COMPONENT}_INCLUDE_DIRS}"
             INTERFACE_LINK_LIBRARIES "${PCL_${COMPONENT}_LINK_LIBRARIES}"
         )

cmake/pcl_targets.cmake

@@ -192,6 +192,7 @@ endmacro()
 # ARGN The source files for the library.
 macro(PCL_ADD_LIBRARY _name _component)
     add_library(${_name} ${PCL_LIB_TYPE} ${ARGN})
+    target_compile_features(${_name} PUBLIC ${PCL_CXX_COMPILE_FEATURES})
     # must link explicitly against boost.
     target_link_libraries(${_name} ${Boost_LIBRARIES})
     if((UNIX AND NOT ANDROID) OR MINGW)