Bug#966574: llvm-10: llvm-config-10 --link-static --libnames includes libPolly.a which is in another package

[Nick Lewycky]

Package: llvm-10
Version: 1:10.0.1-1
Severity: normal

Dear Maintainer,

I'm attempting to use LLVM bindings in Rust, the common bindings are the
llvm-sys crate. To link, they use

   llvm-config-10 --link-static --libnames

to find all the libraries. That list includes libPolly.a which isn't 
installed
as part of llvm-10 but is instead included in libclang-common-10-dev which
may or may not be installed.

The error that I see from a rust user point of view looks like this:

```
nicholas at tracer:~$ cd llvm-sys-user/
nicholas at tracer:~/llvm-sys-user$ cargo build
    Compiling llvm-sys v100.1.0
error: could not find native static library `Polly`, perhaps an -L flag 
is missing?

error: aborting due to previous error

error: could not compile `llvm-sys`.
```

Nick

-- System Information:
Debian Release: bullseye/sid
   APT prefers stable-updates
   APT policy: (500, 'stable-updates'), (500, 'testing'), (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 5.7.0-1-amd64 (SMP w/8 CPU threads)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE 
not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages llvm-10 depends on:
ii  libc6            2.31-2
ii  libgcc-s1        10.1.0-6
ii  libllvm10        1:10.0.1-1
ii  libpfm4          4.10.1+git44-ga2909cd-1
ii  libstdc++6       10.1.0-6
ii  libtinfo6        6.2-1
ii  libz3-4          4.8.8-1
ii  llvm-10-runtime  1:10.0.1-1
ii  zlib1g           1:1.2.11.dfsg-2

Versions of packages llvm-10 recommends:
ii  llvm-10-dev  1:10.0.1-1

Versions of packages llvm-10 suggests:
pn  llvm-10-doc  <none>

-- no debconf information