[NNUE] Wrap aligned_alloc

For some systems std::aligned_alloc is not available even if c++17 is specified.
Wrap the function and use specific solutions.

Update macosx-version-min to the required minimum.

No functional change.

src/misc.h

@@ -33,6 +33,8 @@ const std::string engine_info(bool to_uci = false);
 const std::string compiler_info();
 void prefetch(void* addr);
 void start_logger(const std::string& fname);
+void* std_aligned_alloc(size_t alignment, size_t size);
+void std_aligned_free(void* ptr);
 void* aligned_ttmem_alloc(size_t size, void*& mem);
 void aligned_ttmem_free(void* mem); // nop if mem == nullptr