Fixing build.

src/Common/mmap.cpp

@@ -1,26 +0,0 @@
-#if defined(OS_LINUX)
-#include <cstdlib>
-
-
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wredundant-decls"
-extern "C"
-{
-    void * mmap(void * /*addr*/, size_t /*length*/, int /*prot*/, int /*flags*/, int /*fd*/, off_t /*offset*/);
-    int munmap(void * /*addr*/, size_t /*length*/);
-}
-#pragma GCC diagnostic pop
-
-template<typename T>
-inline void ignore(T x __attribute__((unused)))
-{
-}
-
-static void dummyFunctionForInterposing() __attribute__((used));
-static void dummyFunctionForInterposing()
-{
-    /// Suppression for PVS-Studio and clang-tidy.
-    ignore(mmap(nullptr, 0, 0, 0, 0, 0)); // -V575 NOLINT
-    ignore(munmap(nullptr, 0)); // -V575 NOLINT
-}
-#endif

src/Storages/MergeTree/KeyCondition.cpp

@@ -925,8 +925,8 @@ KeyCondition::KeyCondition(
 {
     for (size_t i = 0, size = key_column_names.size(); i < size; ++i)
     {
-        std::string name = key_column_names[i];
+        const auto & name = key_column_names[i];
-        if (!key_columns.count(name))
+        if (!key_columns.contains(name))
             key_columns[name] = i;
     }