Directory /tmp is now on tmpfs, which can cause problems with limitted space
or replication. It's documented here:
http://dev.mysql.com/doc/refman/5.5/en/server-options.html#option_mysqld_tmpdir

"If the MySQL server is acting as a replication slave, you should not set --tmpdir
to point to a directory on a memory-based file system or to a directory that is
cleared when the server host restarts."

RHBZ#962087
Upstream bug report: https://mariadb.atlassian.net/browse/MDEV-4165
MySQL bug report: http://bugs.mysql.com/bug.php?id=68338

diff -up mysql-5.6.14/CMakeLists.txt.tmpdir mysql-5.6.14/CMakeLists.txt
--- mysql-5.6.14/CMakeLists.txt.tmpdir	2013-09-10 09:38:25.000000000 +0200
+++ mysql-5.6.14/CMakeLists.txt	2013-10-09 14:49:14.115887439 +0200
@@ -309,6 +309,10 @@ IF(SYSCONFDIR)
   SET(DEFAULT_SYSCONFDIR "${SYSCONFDIR}")
 ENDIF()
 
+IF(TMPDIR)
+  SET(DEFAULT_TMPDIR "${TMPDIR}")
+ENDIF()
+
 
 # Run platform tests
 INCLUDE(configure.cmake)
diff -up mysql-5.6.14/config.h.cmake.tmpdir mysql-5.6.14/config.h.cmake
--- mysql-5.6.14/config.h.cmake.tmpdir	2013-09-10 09:38:25.000000000 +0200
+++ mysql-5.6.14/config.h.cmake	2013-10-09 14:49:14.115887439 +0200
@@ -636,6 +636,7 @@
 #cmakedefine DEFAULT_CHARSET_HOME "@DEFAULT_CHARSET_HOME@"
 #cmakedefine PLUGINDIR "@PLUGINDIR@"
 #cmakedefine DEFAULT_SYSCONFDIR "@DEFAULT_SYSCONFDIR@"
+#cmakedefine DEFAULT_TMPDIR "@DEFAULT_TMPDIR@"
 
 #cmakedefine SO_EXT "@CMAKE_SHARED_MODULE_SUFFIX@"
 
diff -up mysql-5.6.14/include/my_global.h.tmpdir mysql-5.6.14/include/my_global.h
--- mysql-5.6.14/include/my_global.h.tmpdir	2013-09-10 09:38:25.000000000 +0200
+++ mysql-5.6.14/include/my_global.h	2013-10-09 14:49:14.116887439 +0200
@@ -1219,3 +1219,10 @@ typedef struct
 #endif
 
 #endif  // MY_GLOBAL_INCLUDED
+/*
+  Define default tmpdir if not already set.
+*/
+#if !defined(DEFAULT_TMPDIR)
+#define DEFAULT_TMPDIR P_tmpdir
+#endif
+
diff -up mysql-5.6.14/libmysqld/lib_sql.cc.tmpdir mysql-5.6.14/libmysqld/lib_sql.cc
--- mysql-5.6.14/libmysqld/lib_sql.cc.tmpdir	2013-09-10 09:38:26.000000000 +0200
+++ mysql-5.6.14/libmysqld/lib_sql.cc	2013-10-09 14:49:14.116887439 +0200
@@ -587,7 +587,7 @@ int init_embedded_server(int argc, char
     opt_mysql_tmpdir=getenv("TMP");
 #endif
   if (!opt_mysql_tmpdir || !opt_mysql_tmpdir[0])
-    opt_mysql_tmpdir=(char*) P_tmpdir;		/* purecov: inspected */
+    opt_mysql_tmpdir=(char*) DEFAULT_TMPDIR;		/* purecov: inspected */
 
   init_ssl();
   umask(((~my_umask) & 0666));
diff -up mysql-5.6.14/mysys/mf_tempdir.c.tmpdir mysql-5.6.14/mysys/mf_tempdir.c
--- mysql-5.6.14/mysys/mf_tempdir.c.tmpdir	2013-09-10 09:38:25.000000000 +0200
+++ mysql-5.6.14/mysys/mf_tempdir.c	2013-10-09 14:49:14.116887439 +0200
@@ -43,7 +43,7 @@ my_bool init_tmpdir(MY_TMPDIR *tmpdir, c
       pathlist=getenv("TMP");
 #endif
     if (!pathlist || !pathlist[0])
-      pathlist=(char*) P_tmpdir;
+      pathlist=(char*) DEFAULT_TMPDIR;
   }
   do
   {
diff -up mysql-5.6.14/mysys/mf_tempfile.c.tmpdir mysql-5.6.14/mysys/mf_tempfile.c
--- mysql-5.6.14/mysys/mf_tempfile.c.tmpdir	2013-09-10 09:38:25.000000000 +0200
+++ mysql-5.6.14/mysys/mf_tempfile.c	2013-10-09 14:49:14.117887440 +0200
@@ -111,7 +111,7 @@ File create_temp_file(char *to, const ch
 				    sizeof(prefix_buff)-7),"XXXXXX") -
 		     prefix_buff);
     if (!dir && ! (dir =getenv("TMPDIR")))
-      dir=P_tmpdir;
+      dir=DEFAULT_TMPDIR;
     if (strlen(dir)+ pfx_len > FN_REFLEN-2)
     {
       errno=my_errno= ENAMETOOLONG;