add portable lchown (trivial to support and a few ancient things want it..)

src/stat/lchmod.c

@@ -0,0 +1,7 @@
+#include <sys/stat.h>
+#include <fcntl.h>
+
+int lchmod(const char *path, mode_t mode)
+{
+	return fchmodat(AT_FDCWD, path, mode, AT_SYMLINK_NOFOLLOW);
+}