efl: fix build failure when it builds with coverage.

efl: fix build failure when it builds with coverage.

Summary:
When src/bin/efl/ builds with [--with-tests=coverage], it fails to find gcov lib.
The gcov/lcov related options has to be passed when it is builded.
And it only contained in EFL_CFLAGS, EFL_LIBS.
@fix

Test Plan:
Be sure the your enviroments to build src/bin/efl/.

1. Run ./autogen.sh --with-tests=coverage
2. make or make check
3. See the build errors.

Reviewers: raster, jpeg, cedric

Reviewed By: cedric

Subscribers: herdsman

Differential Revision: https://phab.enlightenment.org/D3370

Signed-off-by: Cedric BAIL <cedric@osg.samsung.com>