test: fix test run from an external build

Makefile.autosetup is not present in the build tree, so when
we get the "srcdir" config from atf Makefile.autosetup is not present
because it points at the buildir.

tests/lib/pkg_elf.c

@@ -60,7 +60,7 @@ ATF_TC_BODY(analyse_elf, tc)
 	ATF_REQUIRE_STREQ(tll_front(p->shlibs_provided), "libtestfbsd.so.1");
 	free(binpath);
 
-	xasprintf(&binpath, "%s/Makefile.autosetup", atf_tc_get_config_var(tc, "srcdir"));
+	xasprintf(&binpath, "%s/Makefile", atf_tc_get_config_var(tc, "srcdir"));
 	ATF_REQUIRE_EQ(pkg_analyse_elf(false, p, binpath), EPKG_END);
 	ATF_REQUIRE_EQ(tll_length(p->shlibs_provided), 1);
 	free(binpath);