support macOS arm

[toge]

I met compilation errors on macOS arm.
This error seems to be caused by 2 reasons.

First, LINUX_ARM is falsely defined by macOS arm.

#if defined(__ARM_ARCH) || defined(__ARM_NEON) || defined(__ARM_NEON__)
    #if !defined IOS
        #define LINUX_ARM
    #endif
#endif

It causes following compilation error.

gf256.cpp:35:10: fatal error: 'elf.h' file not found
   35 | #include <elf.h>
      |          ^~~~~~~

Second, tmmintrin.h is falsely included on macOS arm.

#if defined(ANDROID) || defined(IOS) || defined(LINUX_ARM) || defined(__powerpc__) || defined(__s390__)
    #define GF256_TARGET_MOBILE
#endif // ANDROID

It causes following compilation error due to including tmmintrin.h.

In file included from gf256.cpp:30:
In file included from gf256.h:75:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/16/include/tmmintrin.h:14:2: error: "This header is only meant to be used on x86 and x64 architecture"
   14 | #error "This header is only meant to be used on x86 and x64 architecture"
      |  ^

This PR tries to fix these issues.