resolv: Rename res_comp.c to res-name-checking.c and move into libc

This reflects what the remaining functions in the file do.

The __res_dnok, __res_hnok, __res_mailok, __res_ownok were moved
with the script, using --no-new-version, and turned into compat
symbols.  __libc_res_dnok@@GLIBC_PRIVATE and
__libc_res_hnok@@GLIBC_PRIVATE are added for internal use, to avoid
accidentally binding to compatibility symbols.  The new public
symbols res_dnok, res_hnok, res_mailok, res_ownok were added using
make update-all-abi.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

69 files changed, 309 insertions, 153 deletions

diff --git a/include/resolv.h b/include/resolv.h
index 378b36d612..0c8db600d6 100644
--- a/include/resolv.h
+++ b/include/resolv.h
@@ -44,8 +44,6 @@ libresolv_hidden_proto (_sethtent)
 libresolv_hidden_proto (_gethtent)
 libresolv_hidden_proto (_gethtbyaddr)
 libresolv_hidden_proto (_gethtbyname2)
-libresolv_hidden_proto (__res_hnok)
-libresolv_hidden_proto (__res_dnok)
 libresolv_hidden_proto (__putlong)
 libresolv_hidden_proto (__putshort)
 libresolv_hidden_proto (__p_cdnname)
@@ -67,6 +65,10 @@ extern __typeof (dn_expand) __libc_dn_expand;
 libc_hidden_proto (__libc_dn_expand)
 extern __typeof (dn_skipname) __libc_dn_skipname;
 libc_hidden_proto (__libc_dn_skipname)
+extern __typeof (res_dnok) __libc_res_dnok;
+libc_hidden_proto (__libc_res_dnok)
+extern __typeof (res_hnok) __libc_res_hnok;
+libc_hidden_proto (__libc_res_hnok)
 
 # endif /* _RESOLV_H_ && !_ISOMAC */
 #endif
diff --git a/resolv/Makefile b/resolv/Makefile
index e1a608f4ac..7e142b9a14 100644
--- a/resolv/Makefile
+++ b/resolv/Makefile
@@ -44,6 +44,7 @@ routines := \
   ns_name_unpack \
   nsap_addr \
   res-close \
+  res-name-checking \
   res-state \
   res_hconf \
   res_init \
@@ -142,7 +143,6 @@ libresolv-routines := \
   ns_samedomain \
   ns_ttl \
   res-putget \
-  res_comp \
   res_data \
   res_debug \
   res_enable_icmp \
diff --git a/resolv/Versions b/resolv/Versions
index 634c7833a8..3e3b89a0b2 100644
--- a/resolv/Versions
+++ b/resolv/Versions
@@ -3,6 +3,10 @@ libc {
     __dn_comp;
     __dn_skipname;
     __h_errno_location;
+    __res_dnok;
+    __res_hnok;
+    __res_mailok;
+    __res_ownok;
     __res_randomid;
     _res;
     dn_expand;
@@ -54,6 +58,10 @@ libc {
     ns_name_skip;
     ns_name_uncompress;
     ns_name_unpack;
+    res_dnok;
+    res_hnok;
+    res_mailok;
+    res_ownok;
   }
   GLIBC_PRIVATE {
 %if !PTHREAD_IN_LIBC
@@ -64,6 +72,8 @@ libc {
     __inet_pton_length;
     __libc_dn_expand;
     __libc_dn_skipname;
+    __libc_res_dnok;
+    __libc_res_hnok;
     __ns_name_compress;
     __ns_name_ntop;
     __ns_name_pack;
@@ -107,12 +117,8 @@ libresolv {
     __putlong;
     __putshort;
     __res_close;
-    __res_dnok;
-    __res_hnok;
     __res_isourserver;
-    __res_mailok;
     __res_nameinquery;
-    __res_ownok;
     __res_queriesmatch;
     __res_send;
     __sym_ntop;
diff --git a/resolv/res_comp.c b/resolv/res-name-checking.c
index 16f7e02111..2c603494fa 100644
--- a/resolv/res_comp.c
+++ b/resolv/res-name-checking.c
@@ -1,4 +1,4 @@
-/* Domain name processing functions.
+/* Syntax checking for DNS domain names.
    Copyright (C) 1995-2021 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
@@ -82,15 +82,9 @@
  * SOFTWARE.
  */
 
-#include <sys/types.h>
-#include <sys/param.h>
-#include <netinet/in.h>
 #include <arpa/nameser.h>
-#include <ctype.h>