Export an interface target for the C++ header-only library

Author: dennisklein

CMakeLists.txt

@@ -204,6 +204,17 @@ IF (BUILD_SHARED_LIBS OR MSGPACK_ENABLE_SHARED)
     )
 ENDIF ()
 
+IF (MSGPACK_ENABLE_CXX AND ((CMAKE_VERSION VERSION_GREATER 3.0) OR (CMAKE_VERSION VERSION_EQUAL 3.0)))
+    ADD_LIBRARY (msgpackc-cxx INTERFACE)
+
+    TARGET_INCLUDE_DIRECTORIES (msgpackc-cxx
+        INTERFACE
+            $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+            $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/include>
+            $<INSTALL_INTERFACE:include>
+    )
+ENDIF ()
+
 IF (MSGPACK_ENABLE_STATIC)
     ADD_LIBRARY (msgpackc-static STATIC
         ${msgpackc_SOURCES}
@@ -307,6 +318,10 @@ IF (BUILD_SHARED_LIBS OR MSGPACK_ENABLE_SHARED)
     SET (MSGPACK_INSTALLTARGETS msgpackc)
 ENDIF ()
 
+IF (MSGPACK_ENABLE_CXX AND ((CMAKE_VERSION VERSION_GREATER 3.0) OR (CMAKE_VERSION VERSION_EQUAL 3.0)))
+    LIST (APPEND MSGPACK_INSTALLTARGETS msgpackc-cxx)
+ENDIF ()
+
 IF (MSGPACK_ENABLE_STATIC)
     LIST (APPEND MSGPACK_INSTALLTARGETS msgpackc-static)
 ENDIF ()