Added backward support for gcc-c++

[navashiva]

Checklist

• py.test passes
• code is well formatted
• further testing on C++ compilers >=10

What does this implement/fix? Explain your changes

Ability to install the package against C/C++ compiler versions <10. Running into following issue during installation of the package

Error: 'isfinite' was not declared in this scope!

The fix is tested against version gcc-c++ version 4.8 that gets shipped with RHEL 7.

[codecov]

Codecov Report

Merging #255 (24b6430) into master (bfd1005) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #255   +/-   ##
=======================================
  Coverage   98.35%   98.35%           
=======================================
  Files          37       37           
  Lines        3229     3229           
  Branches      518      518           
=======================================
  Hits         3176     3176           
  Misses         28       28           
  Partials       25       25           

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