functional build on mac os mojave

src/third_party/websocketpp/websocketpp-config.cmake

@@ -0,0 +1,28 @@
+# - Config file for the websocketpp package
+# It defines the following variables
+#  WEBSOCKETPP_FOUND - indicates that the module was found
+#  WEBSOCKETPP_INCLUDE_DIR - include directories
+
+
+####### Expanded from @PACKAGE_INIT@ by configure_package_config_file() #######
+####### Any changes to this file will be overwritten by the next CMake run ####
+####### The input file was websocketpp-config.cmake.in                            ########
+
+get_filename_component(PACKAGE_PREFIX_DIR "${CMAKE_CURRENT_LIST_DIR}/../../../" ABSOLUTE)
+
+macro(set_and_check _var _file)
+  set(${_var} "${_file}")
+  if(NOT EXISTS "${_file}")
+    message(FATAL_ERROR "File or directory ${_file} referenced by variable ${_var} does not exist !")
+  endif()
+endmacro()
+
+####################################################################################
+set_and_check(WEBSOCKETPP_INCLUDE_DIR "${PACKAGE_PREFIX_DIR}/include")
+set(WEBSOCKETPP_FOUND TRUE)
+
+#This is a bit of a hack, but it works well. It also allows continued support of CMake 2.8
+if(${CMAKE_VERSION} VERSION_GREATER 3.0.0 OR ${CMAKE_VERSION} VERSION_EQUAL 3.0.0)
+  add_library(websocketpp::websocketpp INTERFACE IMPORTED)
+  set_target_properties(websocketpp::websocketpp PROPERTIES INTERFACE_INCLUDE_DIRECTORIES "${WEBSOCKETPP_INCLUDE_DIR}")
+endif()