docs: add initial macos notes for llama.cpp

notes/llama.cpp/macosx.md

@@ -0,0 +1,41 @@
+## Macos notes for llama.cpp
+
+### Building with xcodebuild
+We need to install an iOS platform install to build which can be installed using:
+```console
+$ xcodebuild -downloadPlatform iOS
+```
+
+To build the project with xcodebuild, use the following command:
+```console
+$ xcodebuild -scheme llama -destination "generic/platform=iOS"
+```
+
+### multiple resources named 'ggml-metal.metal' in target 'llama'
+I ran into this issue when trying to build the project with xcodebuild. The error message is:
+```console
+$ xcodebuild -scheme llama -destination "generic/platform=iOS"
+Command line invocation:
+    /Applications/Xcode.app/Contents/Developer/usr/bin/xcodebuild -scheme llama -destination generic/platform=iOS
+
+User defaults from command line:
+    IDEPackageSupportUseBuiltinSCM = YES
+
+Resolve Package Graph
+multiple resources named 'ggml-metal.metal' in target 'llama'multiple resources named 'ggml-metal-embed.metal' in target 'llama'
+
+Resolved source packages:
+  llama: /Users/danbev/work/llama.cpp
+
+2024-11-01 07:02:29.107 xcodebuild[45972:9437010] Writing error result bundle to /var/folders/7h/g216wj3x0qldxw27twph8mwr0000gn/T/ResultBundle_2024-01-11_07-02-0029.xcresult
+xcodebuild: error: Could not resolve package dependencies:
+  multiple resources named 'ggml-metal.metal' in target 'llama'
+  multiple resources named 'ggml-metal-embed.metal' in target 'llama'
+```
+This was due to there being a `ggml-metal.metal` file in the build directory:
+```console
+$ find . -name ggml-metal.metal
+./build/bin/ggml-metal.metal
+./ggml/src/ggml-metal.metal
+```
+Removing this file allowed the build to progress.