libselinux/restorecon: Include <selinux/label.h>

restorecon.h uses types defined in label.h, so it needs to include
label.h (or code using restorecon.h also needs to include label.h,
which is not practical).

Fixes:
  $ make DESTDIR=~/obj install > make.out
In file included from semanage_store.c:39:
/home/sdsmall/obj/usr/include/selinux/restorecon.h:137:52: error:
‘struct selabel_handle’ declared inside parameter list will not be
visible outside of this definition or declaration [-Werror]
  137 | extern void selinux_restorecon_set_sehandle(struct
selabel_handle *hndl);
      |                                                    ^~~~~~~~~~~~~~
cc1: all warnings being treated as errors
make[2]: *** [Makefile:111: semanage_store.o] Error 1
make[1]: *** [Makefile:15: install] Error 2
make: *** [Makefile:40: install] Error 1

Signed-off-by: Vit Mojzis <vmojzis@redhat.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>

libselinux/include/selinux/restorecon.h

@@ -1,6 +1,8 @@
 #ifndef _RESTORECON_H_
 #define _RESTORECON_H_
 
+#include <selinux/label.h>
+
 #include <sys/types.h>
 #include <stddef.h>
 #include <stdarg.h>