MDEV-15583 create_temp_file: remove tempnam implementation

In the spirit of the man page "Never use this function."
lets purge off this implementation. mkstemp is a widely
available alternative.

Closes #661.

cmake/os/WindowsCache.cmake

@@ -239,7 +239,6 @@ SET(HAVE_SYS_VADVISE_H CACHE  INTERNAL "")
 SET(HAVE_SYS_WAIT_H CACHE  INTERNAL "")
 SET(HAVE_TCGETATTR CACHE  INTERNAL "")
 SET(HAVE_TELL 1 CACHE  INTERNAL "")
-SET(HAVE_TEMPNAM 1 CACHE  INTERNAL "")
 SET(HAVE_TERMCAP_H CACHE  INTERNAL "")
 SET(HAVE_TERMIOS_H CACHE  INTERNAL "")
 SET(HAVE_TERMIO_H CACHE  INTERNAL "")

config.h.cmake

@@ -235,7 +235,6 @@
 #cmakedefine HAVE_STRTOUL 1
 #cmakedefine HAVE_STRTOULL 1
 #cmakedefine HAVE_TELL 1
-#cmakedefine HAVE_TEMPNAM 1
 #cmakedefine HAVE_THR_SETCONCURRENCY 1
 #cmakedefine HAVE_THR_YIELD 1
 #cmakedefine HAVE_TIME 1

configure.cmake

@@ -413,7 +413,6 @@ CHECK_FUNCTION_EXISTS (strtoul HAVE_STRTOUL)
 CHECK_FUNCTION_EXISTS (strtoull HAVE_STRTOULL)
 CHECK_FUNCTION_EXISTS (strcasecmp HAVE_STRCASECMP)
 CHECK_FUNCTION_EXISTS (tell HAVE_TELL)
-CHECK_FUNCTION_EXISTS (tempnam HAVE_TEMPNAM)
 CHECK_FUNCTION_EXISTS (thr_setconcurrency HAVE_THR_SETCONCURRENCY)
 CHECK_FUNCTION_EXISTS (thr_yield HAVE_THR_YIELD)
 CHECK_FUNCTION_EXISTS (vasprintf HAVE_VASPRINTF)

mysys/mf_tempfile.c

@@ -132,42 +132,6 @@ File create_temp_file(char *to, const char *dir, const char *prefix,
       my_errno=tmp;
     }
   }
-#elif defined(HAVE_TEMPNAM)
-  {
-    extern char **environ;
-
-    char *res,**old_env,*temp_env[1];
-    if (dir && !dir[0])
-    {				/* Change empty string to current dir */
-      to[0]= FN_CURLIB;
-      to[1]= 0;
-      dir=to;
-    }
-
-    old_env= (char**) environ;
-    if (dir)
-    {				/* Don't use TMPDIR if dir is given */
-      environ=(const char**) temp_env;
-      temp_env[0]=0;
-    }
-
-    if ((res=tempnam((char*) dir, (char*) prefix)))
-    {
-      strmake(to,res,FN_REFLEN-1);
-      (*free)(res);
-      file=my_create(to,0,
-		     (int) (O_RDWR | O_BINARY | O_TRUNC | O_EXCL | O_NOFOLLOW |
-			    O_TEMPORARY | O_SHORT_LIVED),
-		     MYF(MY_WME));
-
-    }
-    else
-    {
-      DBUG_PRINT("error",("Got error: %d from tempnam",errno));
-    }
-
-    environ=(const char**) old_env;
-  }
 #else
 #error No implementation found for create_temp_file
 #endif