Bug#865690: cpp-7: Symlink liblto_plugin.so in /usr/lib/bfd-plugins

[Marc Glisse <marc.glisse@inria.fr>]

Package: cpp-7
Version: 7.1.0-7
Severity: normal

Dear Maintainer,

this package provides the plugin 
/usr/lib/gcc/x86_64-linux-gnu/7/liblto_plugin.so, which is good (not sure 
why it is in package cpp-7 in particular, but I don't care as long as it 
is available). However, binutils look for plugins in /usr/lib/bfd-plugins. 
So by default:

$ cat e.c
int f(double){}
$ g++ e.c -c && nm e.o
0000000000000000 T _Z1fd
$ g++ e.c -c -flto && nm e.o
nm: e.o: plugin needed to handle lto object
0000000000000001 C __gnu_lto_slim
0000000000000001 C __gnu_lto_v1

If I manually create the directory /usr/lib/bfd-plugins and symlink the
plugin there, I do get

$ nm e.o
00000000 T _Z1fd

See for instance https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78795 for
one place where it causes trouble. According to that link, it does not
matter which version of gcc provides the plugin, so you could for
instance provide the symlink with the package cpp from gcc-defaults
(easiest way to have a single version).

-- System Information:
Debian Release: 9.0
  APT prefers unstable-debug
  APT policy: (500, 'unstable-debug'), (500, 'testing'), (500, 'stable'), (50, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386, arm64, ppc64el

Kernel: Linux 4.9.0-3-amd64 (SMP w/8 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages cpp-7 depends on:
ii  gcc-7-base  7.1.0-7
ii  libc6       2.24-12
ii  libgmp10    2:6.1.2+dfsg-1
ii  libisl15    0.18-1
ii  libmpc3     1.0.3-1+b2
ii  libmpfr4    3.1.5-1
ii  zlib1g      1:1.2.8.dfsg-5

cpp-7 recommends no packages.

Versions of packages cpp-7 suggests:
pn  gcc-7-locales  <none>

-- no debconf information