llama : set GGML_NATIVE=OFF and add -mcpu=apple-a12

This commit sets GGML_NATIVE=OFF and adds -mcpu=apple-a12 to the C and
C++ flags for the iOS simulator, iOS device, and macOS builds. This is
an attempt to avoid native compilation and also find a suitable target
architecture with regards to features tha the CPU supports.

build-xcframework.sh

@@ -120,6 +120,7 @@ COMMON_CMAKE_ARGS=(
     -DGGML_BLAS_DEFAULT=${GGML_BLAS_DEFAULT}
     -DGGML_METAL=${GGML_METAL}
     -DGGML_METAL_USE_BF16=${GGML_METAL_USE_BF16}
+    -DGGML_NATIVE=OFF
 )
 
 # Build for iOS simulator
@@ -131,6 +132,8 @@ cmake -B build-ios-sim -G Xcode \
     -DCMAKE_OSX_SYSROOT=iphonesimulator \
     -DCMAKE_OSX_ARCHITECTURES="arm64;x86_64" \
     -DCMAKE_XCODE_ATTRIBUTE_SUPPORTED_PLATFORMS=iphonesimulator \
+    -DCMAKE_C_FLAGS="-mcpu=apple-a12" \
+    -DCMAKE_CXX_FLAGS="-mcpu=apple-a12" \
     -S .
 cmake --build build-ios-sim --config Release
 
@@ -141,6 +144,8 @@ cmake -B build-ios-device -G Xcode \
     -DCMAKE_OSX_SYSROOT=iphoneos \
     -DCMAKE_OSX_ARCHITECTURES="arm64" \
     -DCMAKE_XCODE_ATTRIBUTE_SUPPORTED_PLATFORMS=iphoneos \
+    -DCMAKE_C_FLAGS="-mcpu=apple-a12" \
+    -DCMAKE_CXX_FLAGS="-mcpu=apple-a12" \
     -S .
 cmake --build build-ios-device --config Release
 
@@ -150,6 +155,8 @@ cmake -B build-macos -G Xcode \
     -DCMAKE_OSX_DEPLOYMENT_TARGET=${MACOS_MIN_OS_VERSION} \
     -DCMAKE_OSX_ARCHITECTURES="arm64;x86_64" \
     -DCMAKE_OSX_DEPLOYMENT_TARGET=10.15 \
+    -DCMAKE_C_FLAGS="-mcpu=apple-a12" \
+    -DCMAKE_CXX_FLAGS="-mcpu=apple-a12" \
     -S .
 cmake --build build-macos --config Release