Fix cmake generator evaluation (#251)

Signed-off-by: Mario Dominguez <mariodominguez@eprosima.com>

src/cpp/CMakeLists.txt

@@ -60,7 +60,7 @@ target_compile_definitions(${PROJECT_NAME}
     INTERFACE
     $<$<BOOL:${WIN32}>:${PROJECT_NAME_UPPER}_NO_LIB>
     PUBLIC
-    $<$<STREQUAL:$<TARGET_PROPERTY:${PROJECT_NAME},TYPE>,SHARED_LIBRARY>:${PROJECT_NAME_UPPER}_DYN_LINK>
+    $<$<TARGET_EXISTS:${PROJECT_NAME}>:$<$<STREQUAL:$<TARGET_PROPERTY:${PROJECT_NAME},TYPE>,SHARED_LIBRARY>:${PROJECT_NAME_UPPER}_DYN_LINK>>
     )
 
 # Define public headers