bug#64806: 29.0.92; build process outside srcdir gets stuck

[Van Ly]

When the build process occurs in a directory next to srcdir the make
phase is unable to complete.  See attached File A, line 549 and 1349.

Using configure and make within srcdir builds successfully.  See
attached File Z.

Steps to reproduce:

 1. at srcdir being emacs-29.0.92
 2. run, sh ./autogen.sh
 3. create build directory outside srcdir, mkdir ../emacs-29
 4. at build directory, cd ../emacs-29,
 5. run build process, ../emacs-29.0.92/configure ; make

Expected result:

 The build process completes outside srcdir.

In case this detail is relevant I have CDPATH set in the environment.

Similarly on the emacs master branch the build process won't complete outside 
srcdir.

a-build-fail-L549-L1349.text
Description: File A build process fails outside srcdir

z-build-success-L545-L1224.text
Description: File Z build process succeeds inside srcdir

b-emacs-bug-report.text
Description: File B emacs bug report