Add two new targets related to code coverage: cov and cov-reset
Add two new targets related to code coverage: cov and cov-reset

cov:
  Generate the code coverage report with lcov. Report is generated under: <builddir>/coverage.

cov-reset: Clean up data created by the 'cov' target (remove <builddir>/coverage and reset
counters).  This target is also called by the 'clean' target.

These targets are only available when --enable-coverage has been activated.

CAVEAT:
  Code coverage report relies on files (*.gcno and *.gcda) which are created and compeleted
when you deploy/undeploy the driver and execute the tests.
  More accurately, these files are created by the first program which uses the library. In the
usual test procedure (deploy --> make check --> undeploy), this is the program omx_init
... which must be run under root (kernel module loading).
  As a result, these files are owned by root with restricted permissions, preventing them to be
completed by further test programs, which usually are executed without privileges.

  The current workaround, when you want to perform code coverage, is to modify owner of these files
after having executed 'omx_init start ...'.

Once, you have executed tests and undeployed the driver, you can evaluate the 'cov' target to
generate the HTML report.

NOTICE:
  Code coverage is currently generated only for the library. Helper tools and test programs are
excluded. Moreover, kernel module cannot be compiled for code coverage (mysterious error about an
'unkown EFL symbol' when trying to load the module).

ananos/open-mx,ananos/open-mx,ananos/xen2mx,ananos/xen2mx,ananos/xen2mx,ananos/open-mx,ananos/xen2mx