mc clear prompt for subshell when shell is tcsh and uses their own

[citycat4]

For ages I have tcsh as login shell. And for ages have in .cshrc this prompr setting
set prompt = "%{\033[1;32m%}${mch:q}:%{\033[1;34m%}[$USER]%{\033[1;36m%} \!>%{\033[0m%} "
Prior to 4.8.16 mc uses this format of prompt. Since 4.8.16 it ignores my prompt and uses their own, which I cannot change. To make mc to use my own prompt I forced to edit src/subshell/common.c.