Remove libbacktrace definition of gettid.
Also simplifies the Darwin implementation of gettid, because
apparently libbacktrace had a better way of doing it.
Change-Id: I9e14f9176b167405a5aaa5b8a0db0327c7126271
diff --git a/libbacktrace/BacktraceCurrent.cpp b/libbacktrace/BacktraceCurrent.cpp
index fd1f4da..14f04de 100644
--- a/libbacktrace/BacktraceCurrent.cpp
+++ b/libbacktrace/BacktraceCurrent.cpp
@@ -29,6 +29,8 @@
#include <backtrace/Backtrace.h>
#include <backtrace/BacktraceMap.h>
+#include <cutils/threads.h>
+
#include "BacktraceCurrent.h"
#include "BacktraceLog.h"
#include "ThreadEntry.h"