Now when configuring lustre to build client only the following warning is seen:

configure: WARNING:

Disabling ldiskfs support because complete ext4 source does not exist.

If you are building using kernel-devel packages and require ldiskfs
server support then ensure that the matching kernel-debuginfo-common
and kernel-debuginfo-common-<arch> packages are installed.

In the past when the --disable-server option was used no attempt was made to build ldiskfs at all and no warning was seen.

Suspect this may be an unexpected side effect of the recent commit for LU-3953 config: move ext4 src detection to earlier phase