[Pkg-rust-maintainers] Bug#832565: rustc: don't embed llvm in librustc_llvm

[Ximin Luo]

Package: rustc
Version: 1.10.0+dfsg1-1
Severity: normal

Dear Maintainer,

librustc_llvm-xx.so is approx 30MB, taking about half the space of libstd-rust-xx.
Upstream tells me that this is due to embedding pretty much all of LLVM.

We should explore options to make it instead dynamically link against LLVM,
since that is the Debian convention. (Upstream probably won't spend too much
time on this.) This would reduce the size of libstd-rust-xx by about half.

(The size could further be reduced by splitting dev vs runtime shared objects,
but upstream don't seem to be doing this themselves yet, and any work we do
here should definitely be consulted with them first.)

X

-- System Information:
Debian Release: stretch/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'stable'), (300, 'unstable'), (200, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.4.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_GB.utf8, LC_CTYPE=en_GB.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages rustc depends on:
ii  gcc                   4:5.3.1-3
ii  libc6                 2.23-1
ii  libc6-dev [libc-dev]  2.23-1
ii  libstd-rust-dev       1.10.0+dfsg1-1

Versions of packages rustc recommends:
ii  rust-gdb  1.9.0+dfsg1-1

Versions of packages rustc suggests:
ii  rust-doc  1.10.0~~nightly.20160417+dfsg1-1

-- no debconf information