Bug#939703: sh4: cmake: "Detecting CXX compile features - failed"

[Hilmar Preusse <hille42@web.de>]

Package: g++-9
Version: 9.2.1-7
Severity: important
Tags: ftbfs
Justification: fails to build from source (but built successfully in the past)

Recently I uploaded a new package of texworks to unstable. I noticed that
the new package fails to build on sh4 [1], meanwhile it built fine in the
past [2]. The relevant error message is (AFAICT):

<snip>
-- Detecting CXX compile features
CMake Error: Generator: execution of make failed. Make command was: "/usr/bin/make" "cmTC_bf641/fast"
-- Detecting CXX compile features - failed
-- Git commit info updated
CMake Warning (dev) at CMakeLists.txt:139 (OPTION):
  Policy CMP0077 is not set: option() honors normal variables.  Run "cmake
  --help-policy CMP0077" for policy details.  Use the cmake_policy command to
  set the policy and suppress this warning.

  For compatibility with older versions of CMake, option is clearing the
  normal variable 'BUILD_SHARED_LIBS'.
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) at CMakeLists.txt:146 (OPTION):
  Policy CMP0077 is not set: option() honors normal variables.  Run "cmake
  --help-policy CMP0077" for policy details.  Use the cmake_policy command to
  set the policy and suppress this warning.

  For compatibility with older versions of CMake, option is clearing the
  normal variable 'BUILD_SHARED_PLUGINS'.
This warning is for project developers.  Use -Wno-dev to suppress it.
</snip>

The only change in the new package is the python3 adaption, which should be
not relevant for that error message. The only significant change in the build
tools is that we now use g++-9 instead of g++-8.

I suspect this is a regression in g++-9.

Hilmar

[1] https://buildd.debian.org/status/fetch.php?pkg=texworks&arch=sh4&ver=0.6.3-3&stamp=1567811521&raw=0
[2] https://buildd.debian.org/status/fetch.php?pkg=texworks&arch=sh4&ver=0.6.3-2&stamp=1562792310&raw=0
-- System Information:
Debian Release: bullseye/sid
  APT prefers unstable-debug
  APT policy: (500, 'unstable-debug'), (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 5.2.0-2-amd64 (SMP w/1 CPU core)
Kernel taint flags: TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages g++-9 depends on:
ii  gcc-9            9.2.1-7
ii  gcc-9-base       9.2.1-7
ii  libc6            2.28-10
ii  libgmp10         2:6.1.2+dfsg-4
ii  libisl19         0.20-2
ii  libmpc3          1.1.0-1
ii  libmpfr6         4.0.2-1
ii  libstdc++-9-dev  9.2.1-7
ii  zlib1g           1:1.2.11.dfsg-1+b1

g++-9 recommends no packages.

Versions of packages g++-9 suggests:
pn  g++-9-multilib    <none>
pn  gcc-9-doc         <none>
pn  libstdc++6-9-dbg  <none>

-- no debconf information