builder: use is_dir for src/; changelog: add 0.3.1 features

CHANGELOG.md

@@ -1,3 +1,10 @@
+## V 0.3.1
+*Not released yet*
+- V can now find code in the `src/` directory. This allows making V repos much cleaner.
+- `os.mkdir()` now has an optional `mode` paramter.
+- Full termux support via `$if termux {`.
+- Go backend fixes.
+
 ## V 0.3
 *30 Jun 2022*
 - C to V translation via C2V: `v translate file.c`. (Demo video: [Translating DOOM from C to V, building it in under a second and running it!](https://www.youtube.com/watch?v=6oXrz3oRoEg))

vlib/v/builder/builder.v

@@ -312,7 +312,7 @@ pub fn (b Builder) v_files_from_dir(dir string) []string {
 	if res.len == 0 {
 		// Perhaps the .v files are stored in /src/ ?
 		src_path := os.join_path(dir, 'src')
-		if os.exists(src_path) {
+		if os.is_dir(src_path) {
 			if b.pref.is_verbose {
 				println('v_files_from_dir ("$src_path") (/src/)')
 			}