SERVER-42891 Placate SCons configure subsystem regarding status of dSYM nodes

Author: Andrew Morrow

site_scons/site_tools/separate_debug.py

@@ -80,7 +80,8 @@ def new_emitter(target, source, env):
 
         bitcode_file = None
         if env.TargetOSIs('darwin'):
-            debug_file = env.Dir(str(target[0]) + ".dSYM")
+            debug_file = env.Entry(str(target[0]) + ".dSYM")
+            env.Precious(debug_file)
             if bitcode:
                 bitcode_file = env.File(str(target[0]) + ".bcsymbolmap")
         elif env.TargetOSIs('posix'):