Remove some unused variables

src/attached_probe.cpp

@@ -322,8 +322,7 @@ void AttachedProbe::attach_uprobe()
 void AttachedProbe::attach_usdt(int pid)
 {
   struct bcc_usdt_location loc = {};
-  int err, i;
-  std::ostringstream offset_str;
+  int err;
   void *ctx;
 
   if (pid)

src/list.cpp

@@ -103,7 +103,6 @@ void list_probes(const std::string &search)
     return;
   }
 
-  std::set<std::string> matches;
   size_t loc;
   while (std::getline(file, line))
   {

src/utils-inl.h

@@ -5,7 +5,6 @@
 namespace bpftrace {
 
 inline std::string GetProviderFromPath(std::string path) {
-  std::string provider;
   int i = path.rfind("/");
   return (i != std::string::npos) ? path.substr(i + 1) : path;
 }