-Xcompiler -shared is generally needed when using libtool on Linux, not only when -ld is present

configure

@@ -724,7 +724,6 @@ ISC_PLATFORM_HAVETFO
 ISC_PLATFORM_HAVEIF_LADDRCONF
 ISC_PLATFORM_HAVEIF_LADDRREQ
 BIND9_CO_RULE
-LIBTOOL_ALLOW_UNDEFINED
 LIBTOOL_MODE_UNINSTALL
 LIBTOOL_MODE_LINK
 LIBTOOL_MODE_INSTALL
@@ -15545,14 +15544,11 @@ $as_echo "yes" >&6; }
 		O=lo
 		A=la
 		LIBTOOL_MKDEP_SED='s;\.o;\.lo;'
-		LIBTOOL_MODE_COMPILE='--mode=compile --tag=CC'
-		LIBTOOL_MODE_INSTALL='--mode=install --tag=CC'
-		LIBTOOL_MODE_LINK='--mode=link --tag=CC'
-		LIBTOOL_MODE_UNINSTALL='--mode=uninstall --tag=CC'
+		LIBTOOL_MODE_COMPILE='--mode=compile'
+		LIBTOOL_MODE_INSTALL='--mode=install'
+		LIBTOOL_MODE_LINK='--mode=link'
+		LIBTOOL_MODE_UNINSTALL='--mode=uninstall'
 		INSTALL_LIBRARY='${INSTALL_PROGRAM}'
-		case "$host" in
-		*) LIBTOOL_ALLOW_UNDEFINED= ;;
-		esac
 		;;
 	*)
 		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
@@ -15566,7 +15562,6 @@ $as_echo "no" >&6; }
 		LIBTOOL_MODE_INSTALL=
 		LIBTOOL_MODE_LINK=
 		LIBTOOL_MODE_UNINSTALL=
-		LIBTOOL_ALLOW_UNDEFINED=
 		INSTALL_LIBRARY='${INSTALL_DATA}'
 		;;
 esac
@@ -17608,7 +17603,6 @@ SA=a
-
 BIND9_CO_RULE=".c.$O:"
@@ -20648,24 +20642,15 @@ if test "$with_dlopen" = "yes"; then :
 		 SO_CFLAGS="-fPIC"
 		 SO_LDFLAGS=""
-		 if test "$ac_cv_search_dlopen" != "none required"; then :
-
-			 if test "$use_libtool" = "yes"; then :
-
-				 SO_LDFLAGS="-Xcompiler -shared"
-				 SO_LD="${CC}"
-
-else
-
-				 SO_LDFLAGS="-shared"
-				 SO_LD="${CC}"
-fi
+		 if test "$use_libtool" = "yes"; then :
+			 SO_LDFLAGS="-Xcompiler -shared"
+			 SO_LD="${CC}"
 else
 			 SO_LDFLAGS="-shared"
-			 SO_LD="ld"
+			 SO_LD="${CC}"
 fi
 	        ;; #(

configure.in

@@ -884,14 +884,11 @@ case $use_libtool in
 		O=lo
 		A=la
 		LIBTOOL_MKDEP_SED='s;\.o;\.lo;'
-		LIBTOOL_MODE_COMPILE='--mode=compile --tag=CC'
-		LIBTOOL_MODE_INSTALL='--mode=install --tag=CC'
-		LIBTOOL_MODE_LINK='--mode=link --tag=CC'
-		LIBTOOL_MODE_UNINSTALL='--mode=uninstall --tag=CC'
+		LIBTOOL_MODE_COMPILE='--mode=compile'
+		LIBTOOL_MODE_INSTALL='--mode=install'
+		LIBTOOL_MODE_LINK='--mode=link'
+		LIBTOOL_MODE_UNINSTALL='--mode=uninstall'
 		INSTALL_LIBRARY='${INSTALL_PROGRAM}'
-		case "$host" in
-		*) LIBTOOL_ALLOW_UNDEFINED= ;;
-		esac
 		;;
 	*)
 		AC_MSG_RESULT(no)
@@ -904,7 +901,6 @@ case $use_libtool in
 		LIBTOOL_MODE_INSTALL=
 		LIBTOOL_MODE_LINK=
 		LIBTOOL_MODE_UNINSTALL=
-		LIBTOOL_ALLOW_UNDEFINED=
 		INSTALL_LIBRARY='${INSTALL_DATA}'
 		;;
 esac
@@ -1886,7 +1882,6 @@ AC_SUBST(LIBTOOL_MODE_COMPILE)
 AC_SUBST(LIBTOOL_MODE_INSTALL)
 AC_SUBST(LIBTOOL_MODE_LINK)
 AC_SUBST(LIBTOOL_MODE_UNINSTALL)
-AC_SUBST(LIBTOOL_ALLOW_UNDEFINED)
 
 BIND9_CO_RULE=".c.$O:"
 AC_SUBST(BIND9_CO_RULE)
@@ -2974,17 +2969,12 @@ AS_IF([test "$with_dlopen" = "yes"],
 	       [*-linux*|*-gnu*],[
 		 SO_CFLAGS="-fPIC"
 		 SO_LDFLAGS=""
-		 AS_IF([test "$ac_cv_search_dlopen" != "none required"],[
-			 AS_IF([test "$use_libtool" = "yes"],[
-				 SO_LDFLAGS="-Xcompiler -shared"
-				 SO_LD="${CC}"
-			       ],[
-				 SO_LDFLAGS="-shared"
-				 SO_LD="${CC}"
-			       ])
+		 AS_IF([test "$use_libtool" = "yes"],[
+			 SO_LDFLAGS="-Xcompiler -shared"
+			 SO_LD="${CC}"
 		       ],[
 			 SO_LDFLAGS="-shared"
-			 SO_LD="ld"
+			 SO_LD="${CC}"
 		       ])
 	       ],
 	       [*-freebsd*|*-openbsd*],[