Bug#913946: llvm*-dbgsym not built, lots of 'strip: [something].cpp.o: failed to find link section for section N' errors

[Rebecca N. Palmer]

Source: llvm-toolchain-7
Version: 1:7.0.1~+rc2-3

LLVM 7 no longer builds any debug symbol packages, and at the point in 
the build log where it attempts to do so, there are >1000 messages of 
the form

	strip --strip-debug --remove-section=.comment --remove-section=.note 
--enable-deterministic-archives 
debian/liblld-7/usr/lib/llvm-7/lib/liblldWasm.a
strip: debian/liblld-7/usr/lib/llvm-7/lib/stLkO94N/Driver.cpp.o: failed 
to find link section for section 322
strip: debian/liblld-7/usr/lib/llvm-7/lib/stLkO94N/Driver.cpp.o: failed 
to find link section for section 322
strip: debian/liblld-7/usr/lib/llvm-7/lib/stLkO94N/InputChunks.cpp.o: 
failed to find link section for section 71
strip: debian/liblld-7/usr/lib/llvm-7/lib/stLkO94N/InputChunks.cpp.o: 
failed to find link section for section 71

For most of LLVM's binaries, both of these first happened in 7-9~exp1, 
but as the changes from 7-8 to 7-9~exp1 are not obviously relevant, the 
cause might be outside LLVM itself.

libc++ has had both a few such error messages and no -dbgsym since the 
-7 package first existed.