ggml : fix build broken with -march=armv9-a on MacOS (ggml-org#16520)

* ggml : fix build broken with -march=armv9-a on MacOS

Signed-off-by: Jie Fu <jiefu@tencent.com>

* Add #pragma message

Signed-off-by: Jie Fu <jiefu@tencent.com>

* Address review comment.

Signed-off-by: Jie Fu <jiefu@tencent.com>

* Update ggml/src/ggml-cpu/ggml-cpu.c

---------

Signed-off-by: Jie Fu <jiefu@tencent.com>
Co-authored-by: Diego Devesa <slarengh@gmail.com>

Author: 2 people

ggml/src/ggml-cpu/ggml-cpu-impl.h

@@ -68,7 +68,7 @@ struct ggml_compute_params {
 #endif  // __VXE2__
 #endif  // __s390x__ && __VEC__
 
-#if defined(__ARM_FEATURE_SVE)
+#if defined(__ARM_FEATURE_SVE) && defined(__linux__)
 #include <sys/prctl.h>
 #endif
 

ggml/src/ggml-cpu/ggml-cpu.c

@@ -689,8 +689,13 @@ bool ggml_is_numa(void) {
 #endif
 
 static void ggml_init_arm_arch_features(void) {
-#if defined(__linux__) && defined(__aarch64__) && defined(__ARM_FEATURE_SVE)
+#if defined(__aarch64__) && defined(__ARM_FEATURE_SVE)
+#if defined(__linux__)
     ggml_arm_arch_features.sve_cnt = PR_SVE_VL_LEN_MASK & prctl(PR_SVE_GET_VL);
+#else
+    // TODO: add support of SVE for non-linux systems
+#error "TODO: SVE is not supported on this platform. To use SVE, sve_cnt needs to be initialized here."
+#endif
 #endif
 }