build: make object rule for eolian tests a versioned conditional
automake 1.16 changed the naming of object files:
- When subdir-objects is in effect, Automake will now construct
shorter object file names when no programs and libraries name
clashes are encountered. This should make the discouraged use of
'foo_SHORTNAME' unnecessary in many cases.
https://lists.gnu.org/archive/html/info-gnu/2018-02/msg00008.html
this requires that object-specific rules must be changed to match the new
naming scheme if newer automake is being used. the $am__api_version contains
the version string of the automake version used during autoreconf, so this
should be checked during configure time in order to generate the correct
makefile rule for that automake version
other similar rules should be changed in the same way
note that this conditional speculates on behavior of automake versions past
1.16, which are not yet released and thus may change, meaning that this issue may
reoccur in future automake versions
Differential Revision: https://phab.enlightenment.org/D6594