[CAS] Fix AIX build

[cachemeifyoucan]

Fix AIX build by linking libbsd.a to include implementation for flock.

[amy-kwan]

Sorry for the delayed update - this patch works (thanks!) but it might not be needed. The AIX bot is actually fine with the previous fix for the unused variable (https://lab.llvm.org/buildbot/#/builders/64/builds/5841), so I suspect I might be running into local environment related issues but will report back. I can close this PR if it's not necessary. Thanks again for helping with this and I apologize for the inconvenience!

[amy-kwan]

I believe this patch is not needed, so I will close this PR for now. Thank you again for your assistance in this issue! Greatly appreciate it!

[amy-kwan]

Hi @cachemeifyoucan, hope you don't mind me reopening this PR as this does fix the AIX build this time around. Would you be able to rebase this PR?

[cachemeifyoucan]

@amy-kwan Sure. Rebased. Are you able to reproduce the error I mentioned in the other PR and able to check this PR fixes the problem?

[daltenty]

Change LGTM, flock requires libbsd on AIX:
https://www.ibm.com/docs/en/aix/7.1.0?topic=l-lockfx-lockf-flock-lockf64-subroutine

Thanks!

[amy-kwan]

Thanks @cachemeifyoucan!
Confirmed that this patch resolves the AIX build, so LGTM.

[llvm-ci]

LLVM Buildbot has detected a new failure on builder llvm-clang-x86_64-darwin running on doug-worker-3 while building llvm at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/23/builds/15468

Here is the relevant piece of the build log for the reference

Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang :: Driver/visibility-global-new-delete.cl' FAILED ********************
Exit Code: 127

Command Output (stdout):
--
# RUN: at line 4
/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/clang -### --target=x86_64-unknown-unknown -c -emit-llvm /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/visibility-global-new-delete.cl 2>&1 |    /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/FileCheck -check-prefix=DEFAULTS /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/visibility-global-new-delete.cl
# executed command: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/clang '-###' --target=x86_64-unknown-unknown -c -emit-llvm /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/visibility-global-new-delete.cl
# note: command had no output on stdout or stderr
# executed command: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/FileCheck -check-prefix=DEFAULTS /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/visibility-global-new-delete.cl
# note: command had no output on stdout or stderr
# RUN: at line 12
/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/clang -### --target=x86_64-sie-ps5 -c -emit-llvm /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/visibility-global-new-delete.cl 2>&1 |    /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/FileCheck -check-prefix=PS5 /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/visibility-global-new-delete.cl
# executed command: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/clang '-###' --target=x86_64-sie-ps5 -c -emit-llvm /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/visibility-global-new-delete.cl
# note: command had no output on stdout or stderr
# executed command: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/FileCheck -check-prefix=PS5 /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/visibility-global-new-delete.cl
# note: command had no output on stdout or stderr
# RUN: at line 17
/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/clang -### --target=x86_64-unknown-unknown -c -emit-llvm    -fvisibility-global-new-delete-hidden /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/visibility-global-new-delete.cl 2>&1 | /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/FileCheck -check-prefixes=VGNDH,DEPRECATED /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/visibility-global-new-delete.cl --implicit-check-not=-fvisibility-global-new-delete= --implicit-check-not=-fvisibility-global-new-delete-hidden
# executed command: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/FileCheck -check-prefixes=VGNDH,DEPRECATED /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/visibility-global-new-delete.cl --implicit-check-not=-fvisibility-global-new-delete= --implicit-check-not=-fvisibility-global-new-delete-hidden
# .---command stderr------------
# | Could not create process (/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/FileCheck) due to [Errno 24] Too many open files
# `-----------------------------
# error: command failed with exit status: 127

--

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