perf: emplace elements instead of inserting temporaries

- construct container elements in place instead of inserting a temporary
- clang-tidy modernize-use-emplace
  https://clang.llvm.org/extra/clang-tidy/checks/modernize/use-emplace.html

fairmq/Device.cxx

@@ -513,7 +513,8 @@ void Device::HandleMultipleTransportInput()
     fMultitransportProceed = true;
 
     for (const auto& i : fMultitransportInputs) {
-        threads.emplace_back(thread(&Device::PollForTransport, this, fTransports.at(i.first).get(), i.second));
+        threads.emplace_back(
+            &Device::PollForTransport, this, fTransports.at(i.first).get(), i.second);
     }
 
     for (thread& t : threads) {

fairmq/ProgOptions.cxx

@@ -189,7 +189,7 @@ vector<string> ProgOptions::GetPropertyKeys() const
     vector<string> keys;
 
     for (const auto& it : fVarMap) {
-        keys.push_back(it.first.c_str());
+        keys.emplace_back(it.first.c_str());
     }
 
     return keys;

fairmq/shmem/Manager.h

@@ -390,7 +390,7 @@ class Manager
         }
 
         auto* lRegion = GetRegion(id);
-        fTlRegionCache.fRegionsTLCache.emplace_back(std::make_tuple(lRegion, id, fShmId64));
+        fTlRegionCache.fRegionsTLCache.emplace_back(lRegion, id, fShmId64);
         fTlRegionCache.fRegionsTLCacheGen = fRegionsGen;
         return lRegion;
     }