iox-828 Add CMAKE_INSTALL_RPATH to iceoryx_meta

If iceoryx is built as shared lib we need to set an rpath to the installed shared libs so that roudi can find them

iceoryx_meta/CMakeLists.txt

@@ -25,6 +25,12 @@ include(${CMAKE_CURRENT_SOURCE_DIR}/build_options.cmake)
 include(${CMAKE_CURRENT_SOURCE_DIR}/tests.cmake)
 include(${CMAKE_CURRENT_SOURCE_DIR}/install_help_and_config.cmake)
 
+# set rpath for finding shared libraries outside of the build-tree
+# see https://gitlab.kitware.com/cmake/community/-/wikis/doc/cmake/RPATH-handling#cmake-and-the-rpath
+list(FIND CMAKE_PLATFORM_IMPLICIT_LINK_DIRECTORIES "${CMAKE_INSTALL_PREFIX}/lib" isSystemDir)
+if("${isSystemDir}" STREQUAL "-1")
+    set(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/lib")
+endif()
 
 # ===== Core
 add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/../iceoryx_utils ${CMAKE_BINARY_DIR}/utils)