[lldb][debugserver] Fix build after libcxx removed generic char_traits implementation

[DavidSpickett]

Summary

Which was done in https://reviews.llvm.org/D157058. This follows the fix
for lldb-server in https://reviews.llvm.org/D157589.

[mstorsjo]

LGTM

[DavidSpickett]

I was going to wait for some Mac specific reviewer too but it's simple and the Green Dragon bots should verify it well enough.

lldb/tools/debugserver/source/RNBRemote.cpp

if (reg != NULL) {
     if (reg_value_ptr) {
       append_hex_value(ostrm, reg_value_ptr->value.v_uint8, reg->nub_info.size,
                        false);
     } else {
       // If we fail to read a register value, check if it has a default
       // fail value. If it does, return this instead in case some of
       // the registers are not available on the current system.
       if (reg->nub_info.size > 0) {
-        std::basic_string<uint8_t> zeros(reg->nub_info.size, '\0');
+        std::vector<uint8_t> zeros(reg->nub_info.size, '\0');
         append_hex_value(ostrm, zeros.data(), zeros.size(), false);
       }
     }
   }
 }
 
 void debugserver_regnum_with_fixed_width_hex_register_value(
     std::ostream &ostrm, nub_process_t pid, nub_thread_t tid,
rnb_err_t RNBRemote::HandlePacket_p(const char *p) {
   std::ostringstream ostrm;
   if (reg_entry == NULL) {
     DNBLogError(
         "RNBRemote::HandlePacket_p(%s): unknown register number %u requested\n",
         p, reg);
     ostrm << "00000000";
   } else if (reg_entry->nub_info.reg == (uint32_t)-1) {
     if (reg_entry->nub_info.size > 0) {
-      std::basic_string<uint8_t> zeros(reg_entry->nub_info.size, '\0');
+      std::vector<uint8_t> zeros(reg_entry->nub_info.size, '\0');
       append_hex_value(ostrm, zeros.data(), zeros.size(), false);
     }
   } else {
     register_value_in_hex_fixed_width(ostrm, pid, tid, reg_entry, NULL);
   }
   return SendPacket(ostrm.str());
 }