https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119266
--- Comment #11 from Sam James <sjames at gcc dot gnu.org> ---
(In reply to Sam James from comment #10)
> OK, avoiding speculation and getting back to facts:
> ```
> $ cat ./build/x86_64-pc-linux-gnu/libstdc++-v3/src/c++23/relpath.log
> called with '/usr/lib64' and
> '/usr/lib/gcc/x86_64-pc-linux-gnu/15/include/g++-v15/bits'
> -> called with '/usr/lib64' and
> '/usr/lib/gcc/x86_64-pc-linux-gnu/15/include/g++-v15/bits'
> ```
>
> so toolexeclibdir is /usr/lib64 for me, and includebitsdir is
> /usr/lib/gcc/x86_64-pc-linux-gnu/15/include/g++-v15/bits.
```
# Calculate toolexeclibdir
# Also toolexecdir, though it's only used in toolexeclibdir
case ${version_specific_libs} in
yes)
# Need the gcc compiler version to know where to install libraries
# and header files if --enable-version-specific-runtime-libs option
# is selected.
toolexecdir='$(libdir)/gcc/$(target_noncanonical)'
toolexeclibdir='$(toolexecdir)/$(gcc_version)$(MULTISUBDIR)'
;;
no)
if test -n "$with_cross_host" &&
test x"$with_cross_host" != x"no"; then
# Install a library built with a cross compiler in tooldir, not libdir.
toolexecdir='$(exec_prefix)/$(target_noncanonical)'
case ${with_toolexeclibdir} in
no)
toolexeclibdir='$(toolexecdir)/lib'
;;
*)
toolexeclibdir=${with_toolexeclibdir}
;;
esac
else
toolexecdir='$(libdir)/gcc-lib/$(target_noncanonical)'
toolexeclibdir='$(libdir)'
fi
multi_os_directory=`$CC -print-multi-os-directory`
case $multi_os_directory in
.) ;; # Avoid trailing /.
*) toolexeclibdir=$toolexeclibdir/$multi_os_directory ;;
esac
;;
esac
AC_SUBST(toolexecdir)
AC_SUBST(toolexeclibdir)
```
We currently don't build with version-specific-libs (we probably should, but we
don't right now). Then we end up with toolexeclibdir=libdir.
