[tlbuild] [tlbuilders] llvm-11 compiler bug fix

[Nelson H. F. Beebe]

The LLVM team announced today a bug fix for a broken ABI in the 11.0.1
compilers.  Because some systems now use that compiler family for
/usr/bin/cc, the bug might affect some TeX Live 2021 builds.

Here is the text of the announcement:

>> ...
>> LVM 11.1.0 is now available! Download it now, or read the release notes.
>> 
>> This release contains bug-fixes for the LLVM 11.0.1 release. This
>> is a special release that was made to correct an inadvertent ABI change
>> to libclang.so in 11.0.1.  libclang.so in 11.1.0 is ABI compatible with
>> libclang.so <= 10 and libclang.so >=12, but not with 11.0.1 or 11.0.0.
>> 
>> Binaries and sources for 11.1.0 can be found on GitHub:
>> https://github.com/llvm/llvm-project/releases/tag/llvmorg-11.1.0
>> 
>> LLVM 11.1.0 would not be possible without the help of our volunteer
>> release team! Thanks to all the release testers:
>> 
>> Hans Wennborg, Dimitry Andric, Tobias Hieta, Diana Picus, Albion Fung,
>> Brian Cain, MichaE GC3rny
>> 
>> Also, a big thanks to everyone else who helped identify critical bugs,
>> track down bug-fixes, and resolve merge conflicts.
>> 
>> If you have questions or comments about this release, please contact
>> the LLVMdev mailing list!
>> 
>> LLVM 11.0.1 Release Announcement:
>> https://lists.llvm.org/pipermail/llvm-announce/2021-January/000090.html
>> ...

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- Nelson H. F. Beebe                    Tel: +1 801 581 5254                  -
- University of Utah                    FAX: +1 801 581 4148                  -
- Department of Mathematics, 110 LCB    Internet e-mail: beebe at math.utah.edu  -
- 155 S 1400 E RM 233                       beebe at acm.org  beebe at computer.org -
- Salt Lake City, UT 84112-0090, USA    URL: http://www.math.utah.edu/~beebe/ -
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