cgen: support inc cond for c style for loop with alias types

vlib/v/gen/c/assign.v

@@ -520,7 +520,9 @@ fn (mut g Gen) assign_stmt(node_ ast.AssignStmt) {
 					g.expr(left)
 					g.write(' ${extracted_op} ')
 					g.expr(val)
-					g.write(';')
+					if !g.inside_for_c_stmt {
+						g.write(';')
+					}
 					return
 				} else {
 					g.write(' = ${styp}_${util.replace_op(extracted_op)}(')

vlib/v/slow_tests/inout/alias_for_c_loop_assign_op.out

@@ -0,0 +1,10 @@
+1.0
+2.0
+3.0
+4.0
+5.0
+6.0
+7.0
+8.0
+9.0
+10.0

vlib/v/slow_tests/inout/alias_for_c_loop_assign_op.vv

@@ -0,0 +1,10 @@
+type Float = f32
+
+fn main() {
+	min_value := Float(1)
+	max_value := Float(10)
+	step := Float(1)
+	for n := min_value; n <= max_value; n += step {
+		println('${n}')
+	}
+}