[setup] add basic macos tools (#2332)

script/bootstrap

@@ -61,7 +61,18 @@ install_packages_rpm()
 
 install_packages_brew()
 {
-    echo 'macOS not supported currently' && false
+    # add autotools
+    brew install automake libtool
+
+    # add ARM toolchain
+    brew tap PX4/homebrew-px4
+    brew install gcc-arm-none-eabi
+
+    # check for gcc for posix examples
+    if ! which gcc; then
+        echo 'warning: clang/gcc needed for posix examples'
+        echo 'warning: please install Command Line Tools from https://developer.apple.com/download/more/'
+    fi
 }
 
 install_packages_source()
@@ -86,9 +97,7 @@ install_packages()
 
 main()
 {
-    . $BEFORE_HOOK
     install_packages
-    . $AFTER_HOOK
 }
 
 main