Thanks for the report.
The glibc installing process is calling
./scripts/mkinstalldirs [..]/lib64
which failed to mkdir -p it.
With literal brackets? I don't understand.
+ if test -L "$@"; then
+ echo "mkdir -p -- \"\$(realpath $*)\""
Neither test -L nor (especially) realpath are portable.
(test -h can be used for the former; have to resort to ls -l|sed
for the latter, I think.)
In any case, "resolving" a broken link is a fundamental change in
behavior. I'm doubtful that is desirable at this late date. I'm not
sure it's mkinstalldir's job to figure out that you made a broken
symlink and create the directory it points to. If I'm understanding your
scenario correctly.
What do others think? --thanks, karl.