* nscd/nscd-client.h: New file, broken out of "nscd.h".
* nscd/nscd.h: Move defns needed by clients to "nscd-client.h",
and #include that.
* nscd/Makefile (distribute): Add nscd-client.h.
* nscd/nscd_getgr_r.c, nscd/nscd_gethst_r.c, nscd/nscd_getpw_r.c:
Include "nscd-client.h" instead of "nscd.h"