refactor: remove Windows-specific includes and unused header

- remove conditional Windows malloc.h include
- remove unused algorithm header
- standardise on std::aligned_alloc/std::free for all platforms

Signed-off-by: NotKeira <github.rxs06@accounts.keira.boo>

Author: NotKeira

src/freelist_allocator.cpp

@@ -1,12 +1,6 @@
 #include "freelist_allocator.h"
 #include <cassert>
-#include <algorithm>
-
-#ifdef _WIN32
-#include <malloc.h>
-#else
 #include <cstdlib>
-#endif
 
 namespace fast_alloc
 {
@@ -294,4 +288,4 @@ namespace fast_alloc
 
         return aligned_address;
     }
-} // namespace fast_alloc
+} // namespace fast_alloc

src/freelist_allocator.h

@@ -61,4 +61,4 @@ namespace fast_alloc
             std::size_t& adjustment
         ) noexcept;
     };
-} // namespace fast_alloc
+} // namespace fast_alloc