Fix compilation problem with GCC 9

This fixes issue #580.
6 jobs for master in 403 minutes and 26 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Test
failed #4021
amd64
job_clang_amd64

06:43:26

passed #4025
amd64
job_clang_amd64_nosh

06:38:07

failed #4023
amd64
job_clang_py2_amd64

04:43:10

failed #4020
amd64
job_gcc_amd64

06:31:00

passed #4024
amd64
job_gcc_amd64_nosh

06:16:46

failed #4022
amd64
job_gcc_py2_amd64

04:47:47

 
Name Stage Failure
failed
job_clang_amd64 Test
 1178 tests
3 failures in tests
0 failures in setup code
0 failures in cleanup code
build finished with problems, 19 warnings.
<string>:53: RuntimeWarning: More than 20 figures have been opened. Figures created through the pyplot interface (`matplotlib.pyplot.figure`) are retained until explicitly closed and may consume too much memory. (To control this warning, see the rcParam `figure.max_open_warning`).
<string>:53: RuntimeWarning: More than 20 figures have been opened. Figures created through the pyplot interface (`matplotlib.pyplot.figure`) are retained until explicitly closed and may consume too much memory. (To control this warning, see the rcParam `figure.max_open_warning`).
<string>:1: RuntimeWarning: More than 20 figures have been opened. Figures created through the pyplot interface (`matplotlib.pyplot.figure`) are retained until explicitly closed and may consume too much memory. (To control this warning, see the rcParam `figure.max_open_warning`).
ERROR: Job failed: exit status 1
failed
job_gcc_amd64 Test
  74 tests in default
74 tests in 1 items.
74 passed and 0 failed.
Test passed.

Document: demos/inference/inference
-----------------------------------
bash: line 94: 11267 Segmentation fault (core dumped) python3 /usr/bin/sphinx-build -b doctest . build *.rst demos/inference/inference.rst
ERROR: Job failed: exit status 1
failed
job_gcc_py2_amd64 Test

Exception occurred:
File "/usr/lib/python2.7/site-packages/sphinx/ext/autodoc/__init__.py", line 82, in members_option
return [x.strip() for x in arg.split(',')]
AttributeError: 'bool' object has no attribute 'split'
The full traceback has been saved in /tmp/sphinx-err-gK1l2H.log, if you want to report the issue to the developers.
Please also report this if it was a user error, so that a better error message can be provided next time.
A bug report can be filed in the tracker at <https://github.com/sphinx-doc/sphinx/issues>. Thanks!
ERROR: Job failed: exit status 1
failed
job_clang_py2_amd64 Test

Exception occurred:
File "/usr/lib/python2.7/site-packages/sphinx/ext/autodoc/__init__.py", line 82, in members_option
return [x.strip() for x in arg.split(',')]
AttributeError: 'bool' object has no attribute 'split'
The full traceback has been saved in /tmp/sphinx-err-SRoFJz.log, if you want to report the issue to the developers.
Please also report this if it was a user error, so that a better error message can be provided next time.
A bug report can be filed in the tracker at <https://github.com/sphinx-doc/sphinx/issues>. Thanks!
ERROR: Job failed: exit status 1