toolchain/56180: build.sh fails on OpenBSD 6.9 #2 - liblto plugin major/minor number

[cjep%netbsd.org@localhost]

>Number:         56180
>Category:       toolchain
>Synopsis:       build.sh fails on OpenBSD 6.9 #2 - liblto plugin major/minor number
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    toolchain-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun May 16 12:50:00 +0000 2021
>Originator:     Chris Pinnock
>Release:        NetBSD-current, recent sources as of 16/5/2021
>Organization:
>Environment:
OpenBSD blowfish.home 6.9 GENERIC.MP#473 amd64
OpenBSD clang version 10.0.1
Target: amd64-unknown-openbsd6.9
Thread model: posix

>Description:
cf PR#56179

liblto_plugin is installed in the tools with a major & minor number 0.
The toolchain expects it without a major and minor number. I believe this
is simply the way that OpenBSD handles shared objects. It's not clear
to me here what the best approach is: a) flags to linker; b) flags to
installer; c) symbolic link hack. It looks like this is the only
shared object in our build toolchain.

(A workaround is to copy or symlink the file to liblto_plugin.so)
cjep@blowfish% pwd
/home/cjep/src/NetBSD/obj/amd64-x86_64/home/cjep/usr/src/tooldir.OpenBSD-6.9-amd64/libexec/gcc/x86_64--netbsd/10.3.0
cjep@blowfish% ls -la liblto_plugin.so
-rwxr-xr-x  1 cjep  cjep  113112 May 13 22:05 liblto_plugin.so.0.0

>How-To-Repeat:
Install OpenBSD 6.9
Grab src
./build -U -m amd64 release
(Note that whilst PR#56179 remains open, you will need to skip past the 
nbmakeinfo problem - building tools twice with -u is one way to do it.)


>Fix: