Switch std::call_once to llvm::call_once

Summary:
The std::call_once implementation in libstdc++ has problems on few systems: NetBSD, OpenBSD and Linux PPC. LLVM ships with a homegrown implementation llvm::call_once to help on these platforms.

This change is required in the NetBSD LLDB port. std::call_once with libstdc++ results with crashing the debugger.

Sponsored by <The NetBSD Foundation>

Reviewers: labath, joerg, emaste, mehdi_amini, clayborg

Reviewed By: labath, clayborg

Subscribers: #lldb

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D29288

llvm-svn: 294202

lldb/source/Plugins/Process/POSIX/ProcessPOSIXLog.cpp

@@ -15,6 +15,8 @@
 #include "lldb/Core/StreamFile.h"
 #include "lldb/Interpreter/Args.h"
 
+#include "llvm/Support/Threading.h"
+
 #include "ProcessPOSIXLog.h"
 
 using namespace lldb;
@@ -33,9 +35,9 @@ static Log *GetLog() {
 }
 
 void ProcessPOSIXLog::Initialize(ConstString name) {
-  static std::once_flag g_once_flag;
+  static llvm::once_flag g_once_flag;
 
-  std::call_once(g_once_flag, [name]() {
+  llvm::call_once(g_once_flag, [name]() {
     Log::Callbacks log_callbacks = {DisableLog, EnableLog, ListLogCategories};
 
     Log::RegisterLogChannel(name, log_callbacks);