Add setup-mac-env script (#57)

Author: liss-h

scripts/setup-macos-env.sh

@@ -0,0 +1,55 @@
+#!/bin/bash
+
+if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
+    echo "Error: Script must be sourced, Usage: source $0 <gcc_version>" >&2
+    exit 1
+fi
+
+if [[ -z "$1" ]]; then
+    echo "Error: Missing argument, Usage: source $0 <gcc_version>" >&2
+    return 1
+fi
+
+if ! brew --version > /dev/null 2>&1; then
+    echo "Error: Homebrew missing, install from https://brew.sh/." >&2
+    return 1
+fi
+
+GCC_VERSION="$1"
+
+REQUIRED_FORMULAE=(
+    "gcc@${GCC_VERSION}"
+    "openjdk"
+    "cmake"
+    "ninja"
+)
+
+for formula in "${REQUIRED_FORMULAE[@]}"; do
+    if ! brew list --formula "${formula}" &>/dev/null; then
+        echo "Error: ${formula} missing, install with `brew install ${formula}`" >&2
+        return 1
+    fi
+done
+
+GCC_PREFIX="$(brew --prefix "gcc@${GCC_VERSION}")"
+OPENJDK_PREFIX="$(brew --prefix "openjdk")"
+
+
+# specify minimum support macOS version
+export MACOSX_DEPLOYMENT_TARGET="15.0"
+
+# java needs to be in path
+export PATH="${OPENJDK_PREFIX}/bin:${PATH}"
+
+# apple-clang is completely incompatible to tentris in every way
+# llvm-clang has issues with thread local variables when using libstdc++ and libc++ is completely imcompatible to tentris
+export CC="${GCC_PREFIX}/bin/gcc-${GCC_VERSION}"
+export CXX="${GCC_PREFIX}/bin/g++-${GCC_VERSION}"
+
+# aws-lc-sys requires __ARM_FEATURE_AES and __ARM_FEATURE_SHA2
+# which are only enabled when you pass this option
+# see https://developer.arm.com/documentation/101754/0624/armclang-Reference/armclang-Command-line-Options/-march
+export CFLAGS="-march=armv8-a+aes+sha2"
+
+# rustc needs to be able to find libgcc.a libgcc_s.dylib and libstdc++.a
+export RUSTFLAGS="-L${GCC_PREFIX}/lib/gcc/${GCC_VERSION} -L${GCC_PREFIX}/lib/gcc/${GCC_VERSION}/gcc/aarch64-apple-darwin24/${GCC_VERSION}"