[Devutils] [Set Quilt Vars] Hotfix for both bash and zsh compatibility

devutils/set_quilt_vars.sh

@@ -8,7 +8,7 @@
 alias quilt='quilt --quiltrc -'
 
 # Assume this script lives within devutils/
-PLATFORM_ROOT=$(dirname $(dirname $(readlink -f ${BASH_SOURCE[0]})))
+PLATFORM_ROOT=$(dirname "$(dirname "$(readlink -f "${BASH_SOURCE[0]:-${(%):-%x}}")")")
 
 export QUILT_PATCHES="$PLATFORM_ROOT/patches"
 export QUILT_SERIES="series.merged"