Revert "Print a warning with unknown SCons variables to ease troubleshooting"

This reverts commit 60d1200a265a26c5034f4074ffc507ea52bef526.

SConstruct

@@ -289,13 +289,6 @@ opts.Update(env_base)
 env_base["platform"] = selected_platform  # Must always be re-set after calling opts.Update().
 Help(opts.GenerateHelpText(env_base))
 
-# Detect and print a warning listing unknown SCons variables to ease troubleshooting.
-unknown = opts.UnknownVariables()
-if unknown:
-    print("WARNING: Unknown SCons variables were passed and will be ignored:")
-    for item in unknown.items():
-        print("    " + item[0] + "=" + item[1])
-
 # add default include paths
 
 env_base.Prepend(CPPPATH=["#"])