Changed GRUB config detection function to load from a list inside a variable

config/grub/config/grub.cfg

@@ -80,13 +80,17 @@ set pager=1
 read
 }
 
+# Default list of GRUB possible directories. The @/... entries are for cases where the BTRFS filesystem is being used
+set grub_dirs="boot grub grub2 boot/grub boot/grub2 @/boot @/grub @/grub2 @/boot/grub @/boot/grub2"
+# Default list of GRUB possible config files prefixes
+set grub_conf_names="'' osboot_ autoboot_ libreboot_ coreboot_"
+
 function try_user_grub_config {
 	set root="${1}"
-	# The @/... entries are for cases where the BTRFS filesystem is being used
-	for dir in boot grub grub2 boot/grub boot/grub2 @/boot @/grub @/grub2 @/boot/grub @/boot/grub2; do
+	for dir in ${grub_dirs}; do
 		# In order to save time, we do not attempt anything on non existing directory.
 		if [ -d /"${dir}"/ ]; then
-			for name in '' osboot_ autoboot_ libreboot_ coreboot_; do
+			for name in ${grub_conf_names}; do
 				if [ -f /"${dir}"/"${name}"grub.cfg ]; then
 					unset superusers
 					configfile /"${dir}"/"${name}"grub.cfg