libphobos: Parallelize the libphobos testsuite

libphobos: Parallelize the libphobos testsuite

The removal of the check programs in libphobos means that all tests
will now be compiled one at a time, causing a notable slowdown in
comparison with the previous method of testing.

libphobos/ChangeLog:

2019-04-12  Iain Buclaw  <ibuclaw@gdcproject.org>

	* testsuite/Makefile.am:
	* testsuite/Makefile.am (AUTOMAKE_OPTIONS): Remove dejagnu.
	(RUNTEST): Remove variable.
	(RUNTESTDEFAULTFLAGS, check_p_subno, check_p_numbers0,
	check_p_numbers1, check_p_numbers2, check_p_numbers3,
	check_p_numbers4, check_p_numbers5, check_p_numbers6, check_p_numbers,
	check_p_subdirs, check_DEJAGNU_libphobos_targets): New variables.
	(site.exp, %/site.exp, check-DEJAGNU, check-am, clean-local): New
	rules written so that all the *.exp files are ran parallelized.
	(CLEANFILES): Add *.exe, *.o, and site.exp.
	* testsuite/Makefile.in: Regenerate.

From-SVN: r270303