fsx: Remove environment references

This commit removes the reference to the environment from the fsx
package.

pkg/fsx/dir.go

@@ -0,0 +1,25 @@
+package fsx
+
+import (
+	"io/fs"
+	"os"
+)
+
+// DefaultDirPerm should be used by callers to use a consistent mode for new directories.
+const DefaultDirPerm fs.FileMode = fs.ModeDir | fs.ModePerm
+
+// Mkdir is like [os.Mkdir].
+func Mkdir(path string, mode fs.FileMode) error {
+	m.Lock()
+	defer m.Unlock()
+
+	return os.Mkdir(path, fs.ModeDir|mode)
+}
+
+// MkdirAll is like [os.MkdirAll].
+func MkdirAll(path string, mode fs.FileMode) error {
+	m.Lock()
+	defer m.Unlock()
+
+	return os.MkdirAll(path, fs.ModeDir|mode)
+}