$ ./bootstrap
./bootstrap: Bootstrapping from checked-out hello sources...
./bootstrap: consider installing git-merge-changelog from gnulib
./bootstrap: getting gnulib files...
Submodule 'gnulib' () registered for path 'gnulib'
./bootstrap: getting translations into po/.reference for hello...
receiving incremental file list
sent 34 bytes received 652 bytes 1372.00 bytes/sec
total size is 295770 speedup is 431.15
./bootstrap: updated po//home/rrt/repo/hello/po/.reference.po...
cp: cannot stat `po/.reference//home/rrt/repo/hello/po/.reference.po': No such file or directory
(and then it continued, fine). But it seems to have constructed a bogus filename on the way.