SC2163: Exporting an expansion rather than a variable.

export takes a variable name, but shellcheck has noticed that you give
it an expanded variable instead. The problematic code does not export
MYVAR but a variable called foo if any.

Add exception when using indirections where the variable to extract is
actually the value of the variable.

PR:		227109
Submitted by:	mat
Sponsored by:	Absolight

Mk/Scripts/functions.sh

@@ -197,6 +197,8 @@ export_ports_env() {
 		value="$(eval echo \$${var})"
 
 		if [ -n "${value}" ]; then
+			# shellcheck disable=SC2163
+			# We want to export the variable which name is in var.
 			export ${var}
 			echo "export ${var}=\"${value}\""
 		fi