libxvid: Require availability of mkstemp()

The replacement code uses tempnam(), which is dangerous.
Such a fringe feature is not worth the trouble.

configure

@@ -2290,7 +2290,7 @@ libx262_encoder_deps="libx262"
 libx264_encoder_deps="libx264"
 libx265_encoder_deps="libx265"
 libxavs_encoder_deps="libxavs"
-libxvid_encoder_deps="libxvid"
+libxvid_encoder_deps="libxvid mkstemp"
 
 # demuxers / muxers
 ac3_demuxer_select="ac3_parser"

libavcodec/libxvid_rc.c

@@ -22,9 +22,7 @@
 
 #include "config.h"
 
-#if !HAVE_MKSTEMP
 #include <fcntl.h>
-#endif
 #include <unistd.h>
 #include <xvid.h>
 
@@ -35,36 +33,25 @@
 #include "libxvid.h"
 #include "mpegvideo.h"
 
-/* Wrapper to work around the lack of mkstemp() on mingw.
- * Also, tries to create file in /tmp first, if possible.
+/* Create temporary file using mkstemp(), tries /tmp first, if possible.
  * *prefix can be a character constant; *filename will be allocated internally.
- * @return file descriptor of opened file (or -1 on error)
+ * Return file descriptor of opened file (or error code on error)
  * and opened file name in **filename. */
 int ff_tempfile(const char *prefix, char **filename)
 {
     int fd = -1;
-#if !HAVE_MKSTEMP
-    *filename = tempnam(".", prefix);
-#else
     size_t len = strlen(prefix) + 12; /* room for "/tmp/" and "XXXXXX\0" */
     *filename  = av_malloc(len);
-#endif
-    /* -----common section-----*/
     if (!(*filename)) {
         av_log(NULL, AV_LOG_ERROR, "ff_tempfile: Cannot allocate file name\n");
         return AVERROR(ENOMEM);
     }
-#if !HAVE_MKSTEMP
-    fd = avpriv_open(*filename, O_RDWR | O_BINARY | O_CREAT, 0444);
-#else
     snprintf(*filename, len, "/tmp/%sXXXXXX", prefix);
     fd = mkstemp(*filename);
     if (fd < 0) {
         snprintf(*filename, len, "./%sXXXXXX", prefix);
         fd = mkstemp(*filename);
     }
-#endif
-    /* -----common section-----*/
     if (fd < 0) {
         av_log(NULL, AV_LOG_ERROR, "ff_tempfile: Cannot open temporary file %s\n", *filename);
         return AVERROR(EIO);