guard for multiple includes and multiple definitions

Author: frederic-mahe

src/utils/os_byteswap.hpp

@@ -61,6 +61,9 @@
 // Operating System specific commands to swap bytes
 // C++23 refactoring: replace with std::byteswap()
 
+#ifndef OS_BYTESWAP_HPP
+#define OS_BYTESWAP_HPP
+
 
 #if defined(_MSC_VER) || defined(_WIN32)
 
@@ -146,3 +149,6 @@ constexpr auto bswap_64(uint64_t bsx) noexcept -> uint64_t {
 #include <byteswap.h>
 
 #endif
+
+
+#endif // OS_BYTESWAP_HPP