Re: git: 5e6a2d6eb220 - main - Reapply: move libc++ from /usr/lib to /lib [add /usr/lib/libc++.so.1 -> ../../lib/libc++.so.1 ?]

On 12/31/21 2:59 PM, Mark Millard wrote:
> On 2021-Dec-31, at 14:28, Mark Millard <marklmi@yahoo.com> wrote:
> 
>> On 2021-Dec-30, at 14:04, John Baldwin <jhb@freebsd.org> wrote:
>>
>>> On 12/30/21 1:09 PM, Mark Millard wrote:
>>>> On 2021-Dec-30, at 13:05, Mark Millard <marklmi@yahoo.com> wrote:
>>>>> This asks a question in a different direction that my prior
>>>>> reports about my builds vs. Cy's reported build.
>>>>>
>>>>> Background:
>>>>>
>>>>> /usr/obj/BUILDs/main-amd64-nodbg-clang/usr/main-src/amd64.amd64/tmp/usr/lib/libc++.so:GROUP ( /lib/libc++.so.1 /usr/lib/libcxxrt.so
>>>>> and:
>>>>> lrwxr-xr-x  1 root  wheel        23 Dec 29 13:17:01 2021 /usr/lib/libcxxrt.so -> ../../lib/libcxxrt.so.1
>>>>>
>>>>> Why did libc++.so.1 not get a:
>>>>>
>>>>> /usr/lib/libc++.so.1 -> ../../lib/libc++.so.1
>>>> I forgot to remove the .1 on the left hand side:
>>>> /usr/lib/libc++.so -> ../../lib/libc++.so.1
>>>
>>> Because for libc++.so we don't just symlink to the current version of the library
>>> (as we do for most other shared libraries) to tell the compiler what to link against
>>> for -lc++, instead we use a linker script that tells the compiler to link against
>>> both of those libraries when -lc++ is encountered.
>>
>> A better identification of what looks odd to me is the
>> path variations in:
>>
>> # more /usr/lib/libc++.so
> 
> Another not great day on my part: That path alone makes
> the mix of /lib/ and /usr/lib/ use involved, given the
> reference to /lib/libc++.so.1 . That would still be true
> if the other path had been /lib/libcxxrt.so .

/usr/lib/libc++.so is only used by the compiler/linker when linking a binary.
The resulting binary has the associated paths (/lib/libc++.so.1 and
/usr/lib/libcxxrt.so.1) in its DT_NEEDED.  So it is fine for the .so to be
in /usr/lib.  This is the same with /usr/lib/libc.so vs /lib/libc.so.7.

However, your point about libcxxrt.so.1 is valid.  It needs to also be moved
to /lib if libc++.so.1 is moved to /lib.  Doing so will also require yet another
depend-clean.sh fixup (well, probably just adjusting the one I added to
check the libcxxrt path instead of libc++ path).

-- 
John Baldwin