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

include/sys/stat.h

@@ -86,6 +86,9 @@ int mkdirat(int, const char *, mode_t);
 int mknodat(int, const char *, mode_t, dev_t);
 int mkfifoat(int, const char *, mode_t);
 
+#ifdef _BSD_SOURCE
+int lchmod(const char *, mode_t);
+#endif
 
 #ifdef __cplusplus
 }

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);
+}