[libbacktrace] Rename dtest to btest_gnudebuglink

[libbacktrace] Rename dtest to btest_gnudebuglink

Create a pattern rule for copying an existing test-case, separating out the
debug information into a .debug file, and referencing the .debug file from
the copied test-case using a .gnu_debuglink.

2019-01-25  Tom de Vries  <tdevries@suse.de>

	* Makefile.am: Rewrite dtest rule into "%_gnudebuglink" pattern rule.
	(TESTS): Rename dtest to btest_gnudebuglink.
	* Makefile.in: Regenerate.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@268268 138bc75d-0d04-0410-961f-82ee72b054a4