cmake: make FindRTI search RTI lib subdirs dynamically (x64Linux4gcc8.5.0 etc.)

cmake/FindRTI.cmake

@@ -151,11 +151,17 @@ SET(_lib_vars "")
 
 FOREACH(_lib ${_RTI_LIBS})
   SET(_libname "RTI_${_lib}_LIBRARY")
-  IF (NOT ${_libname})
-    FIND_LIBRARY_WITH_DEBUG("${_libname}"
-                            WIN32_DEBUG_POSTFIX d
-                            NAMES ${_lib}
-                            HINTS ${_rti_library_hint} ${RTI_DIR}/lib ${RTI_DIR}/lib/${_rti_gcc_arch})
+  IF (NOT ${_libname})
+    # Add any arch-specific subdirectories under RTI lib to search hints
+    file(GLOB _rti_lib_candidates RELATIVE "${RTI_DIR}" "${RTI_DIR}/lib/*")
+    set(_rti_lib_full_paths "${RTI_DIR}/lib")
+    foreach(_p IN LISTS _rti_lib_candidates)
+      list(APPEND _rti_lib_full_paths "${RTI_DIR}/lib/${_p}")
+    endforeach()
+    FIND_LIBRARY_WITH_DEBUG("${_libname}"
+                            WIN32_DEBUG_POSTFIX d
+                            NAMES ${_lib}
+                            HINTS ${_rti_library_hint} ${RTI_DIR}/lib ${RTI_DIR}/lib/${_rti_gcc_arch} ${_rti_lib_full_paths})
   ENDIF()
   SET(_tgt_name RTI::${_lib})