Print coverage information after make test

[k4rtik]

Currently we need to execute something like the following to obtain coverage information:

$ gcov pslib_osx.c
File 'pslib_osx.c'
Lines executed:73.56% of 696
pslib_osx.c:creating 'pslib_osx.c.gcov'

It will be good to have this automatically printed at the end of make test.

[k4rtik]

Noufal shared this over email which might be helpful.