Do not clone IPXE since it's a submodule

buildbot/buildbot_steps.sh

@@ -4,12 +4,12 @@
 function clone_ipxe_upstream() {
     local ipxe_src_dir="$1"
 
-    if [ -d "$ipxe_src_dir" ]; then
-        >&2 echo "Clone dir location already exists."
-        return 1
-    fi
+    #if [ -d "$ipxe_src_dir" ]; then
+    #    >&2 echo "Clone dir location already exists."
+    #    return 1
+    #fi
 
-    git clone git://git.ipxe.org/ipxe.git "$ipxe_src_dir" || return 1
+    #git clone git://git.ipxe.org/ipxe.git "$ipxe_src_dir" || return 1
     cd "$ipxe_src_dir"
 
     # Known good commit
@@ -480,3 +480,12 @@ function upload_release_ipxe_shasums() {
 
     return 0
 }
+
+if [[ ! "$(ps -o cmd -p $$ | tail -n 1 | tr -d '\n')" =~ "bash" ]]; then
+    >&2 echo "Shell not bash, exiting."
+    exit 1
+fi
+
+# This is a bash-specific hack to determine if the file is being sourced or
+# run as a script. It will only work in bash, not other shells.
+(return 0 2>/dev/null) || "$@"