Let us take an example of a project that has some tests in a component
that need to be installed into a dedicated test package. The user
expectation is that the result could be achieved by typing the
following:
make
make tests
make install
DESTDIR=/testpkgs make install-tests
However this results in test components in the default installation as
well as the testpkg.
Add an EXCLUDE_FROM_ALL option to the install() command to tell it that
the installation rule should not be included unless its component is
explicitly specified for installation.