Building rcs from rawhide on F26,F27 and other fails: rpmbuild --rebuild rcs-5.9.4-5.fc26.src.rpm ... PASS: t805 FAIL: t810 PASS: t900 .... cd ~/rpmbuild/BUILD/rcs-5.9.4/tests/t810.d/ cat out t810.d/x,v --> t810.d/x revision 4.21 (locked) done t810.d/x,v <-- t810.d/x new revision: 4.22; previous revision: 4.21 done PROBLEM: t810.d/x newer than t810.d/x,v ls shows that the difference is in nanoseconds part of the file timestamp: the file x,v has 0 nanoseconds set by the rcs, and x has nanoseconds set by the OS. ls -ltr --time-style='+%F %T.%N' total 12 -r--r--r--. 1 mal mal 432 2018-01-24 02:03:05.000000000 x,v -rw-r--r--. 1 mal mal 27 2018-01-24 02:03:05.526446950 x -rw-r--r--. 1 mal mal 169 2018-01-24 02:03:05.531446982 out
rcs-5.9.4-5.fc26.src.rpm 20-Feb-2018 11:50 798K still fails with the same "FAIL: t810" error
rcs-5.9.4-9.fc28 has been submitted as an update to Fedora 28. https://bodhi.fedoraproject.org/updates/FEDORA-2018-0ce910523f
rcs-5.9.4-9.fc28 has been pushed to the Fedora 28 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2018-0ce910523f
This is an issue with rcs nanoseconds time handling https://lists.gnu.org/archive/html/bug-rcs/2017-10/msg00007.html it was probably fixed in branch "p": http://git.savannah.gnu.org/cgit/rcs.git/?h=p
rcs-5.9.4-9.fc28 has been pushed to the Fedora 28 stable repository. If problems still persist, please make note of it in this bug report.
This bug (t810 failure) seems to be fixed in git://git.savannah.gnu.org/rcs.git branch "next". But you need to compile the code with -O0 to get working rcs, otherwise gcc miscompiles it.