meta() does not affect keyname() result as expected

[mallachiev]

meta() does not affect keyname() result as expected

As far as keyname() results are cached, after the first call of 
keyname() all the following calls of keyname() with same argument return 
the same result, even if there is a call of meta() that should change 
keyname() return string. Standalone  reproducer is in the attachment.

A possible solution could be to clear the cache in meta() function.

keyname_r.c
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