On linux use sysfs instead of lscpu

Use sysfs (https://www.kernel.org/doc/Documentation/ABI/stable/sysfs-devices-node)
to determine processor to NUMA node mapping.

Avoids problems on some machines with high core count where lscpu was showing high cpu utilization.

closes https://github.com/official-stockfish/Stockfish/pull/5315

No functional change

src/misc.cpp

@@ -42,12 +42,14 @@ using AdjustTokenPrivileges_t =
 #endif
 
 #include <atomic>
+#include <cctype>
 #include <cmath>
 #include <cstdlib>
 #include <fstream>
 #include <iomanip>
 #include <iostream>
 #include <limits>
+#include <iterator>
 #include <mutex>
 #include <sstream>
 #include <string_view>
@@ -603,6 +605,17 @@ size_t str_to_size_t(const std::string& s) {
     return static_cast<size_t>(value);
 }
 
+std::optional<std::string> read_file_to_string(const std::string& path) {
+    std::ifstream f(path, std::ios_base::binary);
+    if (!f)
+        return std::nullopt;
+    return std::string(std::istreambuf_iterator<char>(f), std::istreambuf_iterator<char>());
+}
+
+void remove_whitespace(std::string& s) {
+    s.erase(std::remove_if(s.begin(), s.end(), [](char c) { return std::isspace(c); }), s.end());
+}
+
 std::string CommandLine::get_binary_directory(std::string argv0) {
     std::string pathSeparator;