cgen: fix autofree error of array init with string variable (fix #10427) (#11041)

vlib/v/gen/c/array.v

@@ -110,7 +110,14 @@ fn (mut g Gen) array_init(node ast.ArrayInit) {
 		g.write('\t\t')
 	}
 	for i, expr in node.exprs {
+		if node.expr_types[i] == ast.string_type && expr !is ast.StringLiteral
+			&& expr !is ast.StringInterLiteral {
+			g.write('string_clone(')
+			g.expr(expr)
+			g.write(')')
+		} else {
 			g.expr_with_cast(expr, node.expr_types[i], node.elem_type)
+		}
 		if i != len - 1 {
 			if i > 0 && i & 7 == 0 { // i > 0 && i % 8 == 0
 				g.writeln(',')

vlib/v/tests/valgrind/array_init_with_string_variable.v

@@ -0,0 +1,11 @@
+module main
+
+fn main() {
+	a := 'Hello, '
+	b := 'World!'
+	c := a + b
+
+	d := [a, b, c]
+
+	println(d.len)
+}