tests: enable strace-k.test only for --with-libunwind configurations

Also, since -k option does not support multiple personalities,
add strace-k.test to XFAIL_TESTS when running mpers tests.

* tests/Makefile.am (MPERS_NAME, LIBUNWIND_TESTS, XFAIL_TESTS_,
XFAIL_TESTS_m32, XFAIL_TESTS_mx32, XFAIL_TESTS): New variables.
[USE_LIBUNWIND] (LIBUNWIND_TESTS): Add strace-k.test.
(TESTS): Replace strace-k.test with $(LIBUNWIND_TESTS).
* bootstrap: Substitute MPERS_NAME variable in tests-*/Makefile.am.
* tests/strace-k.test: Do not check for -k option availability.
diff --git a/bootstrap b/bootstrap
index 1044ce2..395fc80 100755
--- a/bootstrap
+++ b/bootstrap
@@ -4,7 +4,8 @@
 	tests=tests-$m
 	rm -rf $tests
 	mkdir $tests
-	sed "s/@arch@/@arch_$m@/;s/^ARCH_MFLAGS[[:space:]]*=.*/& -$m/" \
+	s='[[:space:]]*'
+	sed "s/@arch@/@arch_$m@/;s/^MPERS_NAME$s=.*/& $m/;s/^ARCH_MFLAGS$s=.*/& -$m/" \
 		tests/Makefile.am > $tests/Makefile.am
 	for f in tests/*; do
 		case "${f##*/}" in