test-resume-sig-rt: test unw_resume() in presence of "realtime" signal frame

Introduce a new test case that is derived from test-resume-sig, but
using the SA_SIGINFO sigaction() flag. This case is referred in the
linux kernel sources as "realtime" signal handler, and is handled
differently in the kernel on many architectures and in libunwind as
well.
diff --git a/tests/Makefile.am b/tests/Makefile.am
index dafd1c6..f4f6f3e 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -42,6 +42,7 @@
 			Gtest-init Ltest-init				 \
 			Gtest-concurrent Ltest-concurrent		 \
 			Gtest-resume-sig Ltest-resume-sig		 \
+			Gtest-resume-sig-rt Ltest-resume-sig-rt		 \
 			Gtest-dyn1 Ltest-dyn1				 \
 			Gtest-trace Ltest-trace				 \
 			test-async-sig test-flush-cache test-init-remote \
@@ -154,6 +155,7 @@
 Gtest_exc_LDADD = $(LIBUNWIND) $(LIBUNWIND_local)
 Gtest_init_LDADD = $(LIBUNWIND) $(LIBUNWIND_local)
 Gtest_resume_sig_LDADD = $(LIBUNWIND) $(LIBUNWIND_local)
+Gtest_resume_sig_rt_LDADD = $(LIBUNWIND) $(LIBUNWIND_local)
 Gperf_simple_LDADD = $(LIBUNWIND) $(LIBUNWIND_local)
 Gtest_trace_LDADD=$(LIBUNWIND) $(LIBUNWIND_local)
 Gperf_trace_LDADD = $(LIBUNWIND) $(LIBUNWIND_local)
@@ -166,6 +168,7 @@
 Ltest_nomalloc_LDADD = $(LIBUNWIND_local) @DLLIB@
 Ltest_nocalloc_LDADD = $(LIBUNWIND_local) @DLLIB@ -lpthread
 Ltest_resume_sig_LDADD = $(LIBUNWIND_local)
+Ltest_resume_sig_rt_LDADD = $(LIBUNWIND_local)
 Lperf_simple_LDADD = $(LIBUNWIND_local)
 Ltest_trace_LDADD = $(LIBUNWIND_local)
 Lperf_trace_LDADD = $(LIBUNWIND_local)