GetPrerequisites: Fix call to find_program for `ri` tool

`find_program` does not work with `${a};${b}` as a search path.
Use separate arguments to `PATHS`.

Modules/GetPrerequisites.cmake

@@ -430,8 +430,8 @@ function(gp_resolve_item context item exepath dirs resolved_item_var)
   if(WIN32 AND NOT UNIX)
   if(NOT resolved)
     set(ri "ri-NOTFOUND")
-    find_program(ri "${item}" PATHS "${exepath};${dirs}" NO_DEFAULT_PATH)
-    find_program(ri "${item}" PATHS "${exepath};${dirs}")
+    find_program(ri "${item}" PATHS ${exepath} ${dirs} NO_DEFAULT_PATH)
+    find_program(ri "${item}" PATHS ${exepath} ${dirs})
     if(ri)
       #message(STATUS "info: 'find_program' in exepath/dirs (${ri})")
       set(resolved 1)