cgen: fix selector call with reserved c name (fix #23170) (#23175)

Author: felipensp

vlib/v/gen/c/fn.v

@@ -2180,7 +2180,7 @@ fn (mut g Gen) fn_call(node ast.CallExpr) {
 		// Skip "C."
 		name = util.no_dots(name[2..])
 	} else {
-		name = c_fn_name(name)
+		name = if is_selector_call { c_name(name) } else { c_fn_name(name) }
 	}
 	if g.pref.translated || g.file.is_translated || node.is_file_translated {
 		// For `@[c: 'P_TryMove'] fn p_trymove( ... `

vlib/v/tests/selector_call_with_reserved_c_name_test.v

@@ -0,0 +1,21 @@
+struct Foo {
+}
+
+struct Bar {
+	do fn () bool = unsafe { nil }
+}
+
+fn (f Foo) get() Bar {
+	return Bar{
+		do: foobar
+	}
+}
+
+fn foobar() bool {
+	return true
+}
+
+fn test_main() {
+	t := Foo{}
+	assert t.get().do() == true
+}