Commit bec2ee77f78b4bb8a503101091272a634a273a1c started quoting paths
discovered as part of the `probe` function, which includes git. The
`make` `wildcard` function appears to be incompatible with quoted
paths so this check in the makefile now fails. Employing `wildcard`
here appears to only re-verify that git actually exists, which the
configure script already did, so I've just removed it.
Additionally, with the quoted paths the `subst` function should no
longer be needed, so I've removed it as well.
Closes#18771
7c36336c6f