Merge remote repo native into ext/native/.

ext/native/base/backtrace.cpp

@@ -0,0 +1,22 @@
+#include "base/backtrace.h"
+
+#if defined(__GLIBC__) && !defined(__UCLIBC__)
+#include <execinfo.h>
+#include <unistd.h>
+
+static void *backtrace_buffer[128];
+
+void PrintBacktraceToStderr() {
+	int num_addrs = backtrace(backtrace_buffer, 128);
+	backtrace_symbols_fd(backtrace_buffer, num_addrs, STDERR_FILENO);
+}
+
+#else
+
+#include <stdio.h>
+
+void PrintBacktraceToStderr() {
+	fprintf(stderr, "No backtrace available to print on this platform\n");
+}
+
+#endif