rpm/group-source-files.pl: Deal with {pre,post}fixed / in location
When the source file location provided with -L is either prefixed or
postfixed with forward slash, the script get stuck in a infinite loop
inside calc_dirs() where $path is an empty string.
user@localhost:/tmp> perl "$HOME/group-source-files.pl" -D devel.files -N nondevel.files -L /usr/src/linux-5.14.21-150500.41/
...
path = /usr/src/linux-5.14.21-150500.41/Documentation/Kconfig
path = /usr/src/linux-5.14.21-150500.41/Documentation
path = /usr/src/linux-5.14.21-150500.41
path = /usr/src
path = /usr
path =
path =
path =
... # Stuck in an infinite loop
This workarounds the issue by breaking out the loop once path is an
empty string. For a proper fix we'd want something that
filesystem-aware, but this workaround should be enough for the rare
occation that this script is ran manually.
Link: http://mailman.suse.de/mlarch/SuSE/kernel/2023/kernel.2023.03/msg00024.html