remove use of Mutex in favour of std::{,recursive_}mutex

This is a pretty straightforward first pass over removing a number of uses of
Mutex in favor of std::mutex or std::recursive_mutex. The problem is that there
are interfaces which take Mutex::Locker & to lock internal locks. This patch
cleans up most of the easy cases. The only non-trivial change is in
CommandObjectTarget.cpp where a Mutex::Locker was split into two.

llvm-svn: 269877
diff --git a/lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.h b/lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.h
index 5b313bf..47fba08 100644
--- a/lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.h
+++ b/lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.h
@@ -12,8 +12,9 @@
 
 // C Includes
 // C++ Includes
-#include <vector>
+#include <mutex>
 #include <string>
+#include <vector>
 
 // Other libraries and framework includes
 // Project includes
@@ -21,7 +22,6 @@
 #include "lldb/Host/FileSpec.h"
 #include "lldb/Host/TimeValue.h"
 #include "lldb/Core/UUID.h"
-#include "lldb/Host/Mutex.h"
 #include "lldb/Target/Process.h"
 
 class DynamicLoaderDarwinKernel : public lldb_private::DynamicLoader
@@ -361,7 +361,7 @@
     lldb_private::Address          m_kext_summary_header_addr;
     OSKextLoadedKextSummaryHeader  m_kext_summary_header;
     KextImageInfo::collection      m_known_kexts;
-    mutable lldb_private::Mutex    m_mutex;
+    mutable std::recursive_mutex m_mutex;
     lldb::user_id_t                m_break_id;
 
 private: