Bug#54466 client 5.5 built from source lacks "pager" support

#ifdef THREAD removed from mysql.cc.
               No reason was found for this limitation to persist.

per-file comments:
  client/mysql.cc
Bug#54466      client 5.5 built from source lacks "pager" support
        now we have USE_POPEN always if not __WIN__
  mysql-test/r/mysql.result
Bug#54466      client 5.5 built from source lacks "pager" support
        result updated.
  mysql-test/t/mysql.test
Bug#54466      client 5.5 built from source lacks "pager" support
        test case added.

client/mysql.cc

@@ -93,6 +93,7 @@ extern "C" {
 #else
 #include <readline/readline.h>
 #define HAVE_READLINE
+#define USE_POPEN
 #endif
   //int vidattr(long unsigned int attrs);	// Was missing in sun curses
 }
@@ -108,10 +109,6 @@ extern "C" {
 #define cmp_database(cs,A,B) strcmp((A),(B))
 #endif
 
-#if !defined(__WIN__) && !defined(THREAD)
-#define USE_POPEN
-#endif
-
 #include "completion_hash.h"
 
 #define PROMPT_CHAR '\\'

mysql-test/r/mysql.result

@@ -432,5 +432,8 @@ Bug #47147: mysql client option --skip-column-names does not apply to vertical o
 
 *************************** 1. row ***************************
 1
+Bug #54466 client 5.5 built from source lacks "pager" support
+a
+1
 
 End of tests

mysql-test/t/mysql.test

@@ -425,5 +425,11 @@ drop table t1;
 --echo
 --exec $MYSQL --skip-column-names --vertical test -e "select 1 as a"
 
+#
+# Bug #54466 client 5.5 built from source lacks "pager" support
+# 
+--echo Bug #54466 client 5.5 built from source lacks "pager" support
+--exec $MYSQL --pager test -e "select 1 as a"
+
 --echo
 --echo End of tests