os: add a glob() function (#10497)

vlib/os/glob_test.v

@@ -0,0 +1,62 @@
+import os
+
+fn deep_glob() ? {
+	os.chdir(@VMODROOT)
+	matches := os.glob('vlib/v/*/*.v') or { panic(err) }
+	assert matches.len > 10
+	assert 'vlib/v/ast/ast.v' in matches
+	assert 'vlib/v/ast/table.v' in matches
+	assert 'vlib/v/token/token.v' in matches
+	for f in matches {
+		if !f.starts_with('vlib/v/') {
+			assert false
+		}
+		assert f.ends_with('.v')
+	}
+}
+
+fn test_glob_can_find_v_files_3_levels_deep() ? {
+	$if !windows {
+		deep_glob() ?
+	}
+	assert true
+}
+
+fn test_glob_can_find_files_in_current_folder() ? {
+	os.chdir(@VMODROOT)
+	matches := os.glob('*') ?
+	assert 'README.md' in matches
+	assert 'v.mod' in matches
+	assert 'cmd/' in matches
+	assert 'vlib/' in matches
+	for f in matches {
+		assert !f.ends_with('.v')
+	}
+}
+
+fn test_glob_can_be_used_with_multiple_patterns() ? {
+	os.chdir(@VMODROOT)
+	matches := os.glob('*', 'cmd/tools/*') ?
+	assert 'README.md' in matches
+	assert 'Makefile' in matches
+	$if !windows {
+		assert 'cmd/tools/test_if_v_test_system_works.v' in matches
+	}
+	$if windows {
+		assert 'test_if_v_test_system_works.v' in matches
+	}
+}
+
+fn test_glob_star() ? {
+	os.chdir(@VMODROOT)
+	matches := os.glob('*ake*') ?
+	assert 'Makefile' in matches
+	assert 'make.bat' in matches
+}
+
+fn test_glob_not_found() ? {
+	os.glob('an_unknown_folder/*.v') or {
+		assert true
+		return
+	}
+}