Phylanx remote run test fails to build

[khuck]

Two different tests fail to link with gcc 7:

see http://omega.nic.uoregon.edu:8020/#/builders/5/builds/24/steps/16/logs/stdio

CMakeFiles/remote_run_test_exe.dir/remote_run.cpp.o: In function `hpx::init(hpx::program_options::options_description const&, int, char**, hpx::runtime_mode)':
/var/lib/buildbot/slaves/phylanx/x86_64-gcc7-debug/build/tools/buildbot/src/hpx/hpx/hpx_init_impl.hpp:174: undefined reference to `hpx_main(boost::program_options::variables_map&)'
CMakeFiles/remote_run_test_exe.dir/remote_run.cpp.o: In function `hpx::init(int, char**, hpx::runtime_mode)':
/var/lib/buildbot/slaves/phylanx/x86_64-gcc7-debug/build/tools/buildbot/src/hpx/hpx/hpx_init_impl.hpp:218: undefined reference to `hpx_main(boost::program_options::variables_map&)'
collect2: error: ld returned 1 exit status
make[3]: *** [bin/remote_run_test] Error 1
make[3]: Target `tests/unit/distributed/CMakeFiles/remote_run_test_exe.dir/build' not remade because of errors.
make[2]: *** [tests/unit/distributed/CMakeFiles/remote_run_test_exe.dir/all] Error 2
...
[100%] Linking CXX executable ../../../bin/remote_add_test
CMakeFiles/remote_add_test_exe.dir/remote_add.cpp.o: In function `hpx::init(hpx::program_options::options_description const&, int, char**, hpx::runtime_mode)':
/var/lib/buildbot/slaves/phylanx/x86_64-gcc7-debug/build/tools/buildbot/src/hpx/hpx/hpx_init_impl.hpp:174: undefined reference to `hpx_main(boost::program_options::variables_map&)'
CMakeFiles/remote_add_test_exe.dir/remote_add.cpp.o: In function `hpx::init(int, char**, hpx::runtime_mode)':
/var/lib/buildbot/slaves/phylanx/x86_64-gcc7-debug/build/tools/buildbot/src/hpx/hpx/hpx_init_impl.hpp:218: undefined reference to `hpx_main(boost::program_options::variables_map&)'
collect2: error: ld returned 1 exit status
make[3]: *** [bin/remote_add_test] Error 1
make[3]: Target `tests/unit/distributed/CMakeFiles/remote_add_test_exe.dir/build' not remade because of errors.
make[2]: *** [tests/unit/distributed/CMakeFiles/remote_add_test_exe.dir/all] Error 2
make[2]: Target `tests/CMakeFiles/tests.unit.dir/all' not remade because of errors.
make[1]: *** [tests/CMakeFiles/tests.unit.dir/rule] Error 2
make[1]: Target `tests.unit' not remade because of errors.
make: *** [tests.unit] Error 2
program finished with exit code 2