Getting compilation error with latest codebase on Mac OS with gcc/g++ 9

[yakneens]

In file included from /Users/siakhnin/tools/ont/neusomatic/neusomatic/include/bedio.hpp:8,
                 from /Users/siakhnin/tools/ont/neusomatic/neusomatic/cpp/scan_alignments.cpp:31:
/Users/siakhnin/tools/ont/neusomatic/neusomatic/include/Interval.hpp: At global scope:
/Users/siakhnin/tools/ont/neusomatic/neusomatic/include/Interval.hpp:41:8: error: 'coverage' function with trailing return type has 'decltype(auto)' as its type rather than plain 'auto'
   41 | inline decltype (auto) coverage(const std::vector<Interval>& invs) -> std::vector<typename Interval::Depth> {
      |        ^~~~~~~~
/Users/siakhnin/tools/ont/neusomatic/neusomatic/include/Interval.hpp: In member function 'std::vector<T> neusomatic::bio::IRanges<Interval, half_open>::reduce() const':
/Users/siakhnin/tools/ont/neusomatic/neusomatic/include/Interval.hpp:298:49: error: 'coverage' was not declared in this scope
  298 |     std::vector<typename Interval::Depth> cov = coverage<Interval, true> (invs_);
      |                                                 ^~~~~~~~
/Users/siakhnin/tools/ont/neusomatic/neusomatic/include/Interval.hpp:298:66: error: expected primary-expression before ',' token
  298 |     std::vector<typename Interval::Depth> cov = coverage<Interval, true> (invs_);
      |                                                                  ^
/Users/siakhnin/tools/ont/neusomatic/neusomatic/include/Interval.hpp: In member function 'std::vector<T> neusomatic::bio::IRanges<Interval, half_open>::disjoint() const':
/Users/siakhnin/tools/ont/neusomatic/neusomatic/include/Interval.hpp:341:49: error: 'coverage' was not declared in this scope
  341 |     std::vector<typename Interval::Depth> cov = coverage<Interval, true> (invs_);
      |                                                 ^~~~~~~~
/Users/siakhnin/tools/ont/neusomatic/neusomatic/include/Interval.hpp:341:66: error: expected primary-expression before ',' token
  341 |     std::vector<typename Interval::Depth> cov = coverage<Interval, true> (invs_);
      |                        

...                                          ^
make[2]: *** [cpp/CMakeFiles/scan_alignments.dir/scan_alignments.cpp.o] Error 1
make[1]: *** [cpp/CMakeFiles/scan_alignments.dir/all] Error 2
make: *** [all] Error 2

[msahraeian]

@llevar I am happy to see your interest in NeuSomatic. Currently, NeuSomatic supports g++ 5.4.0. We plan to adapt it for later g++ versions in future releases.