Fail to build on Mac M2

Build step
```
mkdir build
cd build
cmake ..
make
```
Error log
```
/src/cpu/loongarch_utils.h:17:10: fatal error: 'sys/auxv.h' file not found
#include
^~~~~~~~~~~~
1 error generated.
```

Possible fix
```
diff --git a/src/cpu/loongarch_utils.h b/src/cpu/loongarch_utils.h
index b69694d..571e83f 100644
--- a/src/cpu/loongarch_utils.h
+++ b/src/cpu/loongarch_utils.h
@@ -14,7 +14,9 @@
#include
#include
#include
+#if !defined(__APPLE__)
#include
+#endif

namespace megpeak {
enum class SIMDType {
```

The failure is reported in src/cpu/loongarch_utils.h; start by reproducing the documented mkdir, cmake, and make steps on a Mac M2 and inspect the platform-specific include. Done means the project builds successfully on that platform while the existing non-Apple build path remains intact.

Written by the indexing model from the issue text.