DynamicLibraryTest fails with musl libc

Hi all,

on Exherbo (we have downstream patches to adjust some paths to our
directory structures, not sure if that's relevant here though) I'm
seeing the
following test failure on a x86_64-pc-linux-musl system (tests pass
fine on a system glibc system):

[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from DynamicLibrary
[ RUN ] DynamicLibrary.Shutdown
/var/tmp/paludis/build/dev-lang-llvm-10.0.0/work/llvm-project/llvm/unittests/Support/DynamicLibrary/DynamicLibraryTest.cpp:156:
Failure
       Expected: A
       Which is: "PipSqueak"
To be equal to: "Global::~Global"
/var/tmp/paludis/build/dev-lang-llvm-10.0.0/work/llvm-project/llvm/unittests/Support/DynamicLibrary/DynamicLibraryTest.cpp:157:
Failure
       Expected: B
       Which is: "Local::Local(SecondLib)"
To be equal to: "Local::~Local"
/var/tmp/paludis/build/dev-lang-llvm-10.0.0/work/llvm-project/llvm/unittests/Support/DynamicLibrary/DynamicLibraryTest.cpp:162:
Failure
       Expected: Order.size()
       Which is: 0
To be equal to: 2UL
       Which is: 2