Bug#919308: scotch: do not use mpicc

[Drew Parsons]

Package: scotch
Version: 6.0.6-2
Followup-For: Bug #919308

Two questions on the patch to use pkg-config instead of mpicc
to build scotch.

The mpicc docs say that if you need to specify a compiler instead of
using mpicc, then you can get mpi flags via 
  mpicc -showme:compile
  mpicc -showme:link
  
But there is a discrepancy in the link flags:

$pkg-config --libs mpi-c
-L/usr/lib/x86_64-linux-gnu/openmpi/lib -lmpi

$ mpicc -showme:link
-pthread -L/usr/lib/x86_64-linux-gnu/openmpi/lib -lmpi

i.e. pkg-config misses the -pthread link flag. It is provided in
cflags, but if I read the gcc docs correctly it should also be
provided separately as a link flag.  Perhaps this is a bug in mpicc's
pkg-config files.


The second question is that you've assigned `pkg-config -libs mpi-c` to
LDFLAGS.  This means that for linking C++ code, it will miss the
-lmpi_cxx flag. Not a problem for scotch in practice since it is C,
not C++, but something to keep in mind.


Drew



-- System Information:
Debian Release: bullseye/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.19.0-5-amd64 (SMP w/4 CPU cores)
Kernel taint flags: TAINT_WARN, TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=en_AU.UTF-8, LC_CTYPE=en_AU.UTF-8 (charmap=UTF-8), LANGUAGE=en_AU.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages scotch depends on:
ii  libbz2-1.0     1.0.6-9.2
ii  libc6          2.28-10
ii  liblzma5       5.2.4-1
ii  libopenmpi3    3.1.3-11
ii  libscotch-6.0  6.0.6-2
ii  zlib1g         1:1.2.11.dfsg-1

scotch recommends no packages.

scotch suggests no packages.

-- no debconf information