Fix more functions in Args to use StringRef.

This patch also marks the const char* versions as =delete to prevent
their use.  This has the potential to cause build breakages on some
platforms which I can't compile.  I have tested on Windows, Linux,
and OSX.  Best practices for fixing broken callsites are outlined in
Args.h in a comment above the deleted function declarations.

Eventually we can remove these =delete declarations, but for now they
are important to make sure that all implicit conversions from
const char * are manually audited to make sure that they do not invoke a
conversion from nullptr.

llvm-svn: 281919
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
index 0d7ca3c..9dfb47d 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
@@ -946,7 +946,8 @@
   packet.SetFilePos(::strlen("QEnvironment:"));
   const uint32_t bytes_left = packet.GetBytesLeft();
   if (bytes_left > 0) {
-    m_process_launch_info.GetEnvironmentEntries().AppendArgument(packet.Peek());
+    m_process_launch_info.GetEnvironmentEntries().AppendArgument(
+        llvm::StringRef::withNullAsEmpty(packet.Peek()));
     return SendOKResponse();
   }
   return SendErrorResponse(12);
@@ -960,7 +961,7 @@
   if (bytes_left > 0) {
     std::string str;
     packet.GetHexByteString(str);
-    m_process_launch_info.GetEnvironmentEntries().AppendArgument(str.c_str());
+    m_process_launch_info.GetEnvironmentEntries().AppendArgument(str);
     return SendOKResponse();
   }
   return SendErrorResponse(12);
@@ -1032,8 +1033,7 @@
                 if (arg_idx == 0)
                   m_process_launch_info.GetExecutableFile().SetFile(arg.c_str(),
                                                                     false);
-                m_process_launch_info.GetArguments().AppendArgument(
-                    arg.c_str());
+                m_process_launch_info.GetArguments().AppendArgument(arg);
                 if (log)
                   log->Printf("LLGSPacketHandler::%s added arg %d: \"%s\"",
                               __FUNCTION__, actual_arg_index, arg.c_str());