Try running purge before unpacking Mac SDK 10.9 (actions/runner-images#2619)

Author: langmm

utils/setup_old_mac_sdk.sh

@@ -12,6 +12,7 @@ echo "SDKROOT = ${SDKROOT}"
 if [[ ! -d ${CONDA_BUILD_SYSROOT} || "$OSX_FORCE_SDK_DOWNLOAD" == "1" ]]; then
     echo "Downloading ${MACOSX_DEPLOYMENT_TARGET} sdk to ${CONDA_BUILD_SYSROOT}"
     curl -L -O https://github.com/phracker/MacOSX-SDKs/releases/download/10.13/MacOSX${MACOSX_DEPLOYMENT_TARGET}.sdk.tar.xz
+    sudo /usr/sbin/purge
     tar -xf MacOSX${MACOSX_DEPLOYMENT_TARGET}.sdk.tar.xz -C "$(dirname "$CONDA_BUILD_SYSROOT")"
     ls "$(dirname "$CONDA_BUILD_SYSROOT")"
     # set minimum sdk version to our target