avutil/file: Properly deprecate av_tempfile()

It has been deprecated in b4f59beeb4,
but the attribute_deprecated was not set and there was no entry
in APIchanges. This commit adds these and schedules it for removal.
Given that the reason behind the deprecation is exactly the same
as in av_fopen_utf8(), reuse its FF_API_AV_FOPEN_UTF8.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

doc/APIchanges

@@ -14,6 +14,9 @@ libavutil:     2021-04-27
 
 API changes, most recent first:
 
+2022-09-03 - xxxxxxxxxx - lavu 57.35.100 - file.h
+  Deprecate av_tempfile() without replacement.
+
 2022-08-03 - xxxxxxxxxx - lavu 57.34.100 - pixfmt.h
   Add AV_PIX_FMT_VUYX.
 

libavutil/file.c

@@ -155,6 +155,8 @@ void av_file_unmap(uint8_t *bufptr, size_t size)
 #endif
 }
 
+#if FF_API_AV_FOPEN_UTF8
 int av_tempfile(const char *prefix, char **filename, int log_offset, void *log_ctx) {
     return avpriv_tempfile(prefix, filename, log_offset, log_ctx);
 }
+#endif

libavutil/file.h

@@ -22,6 +22,7 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include "version.h"
 #include "attributes.h"
 
 /**
@@ -55,6 +56,7 @@ int av_file_map(const char *filename, uint8_t **bufptr, size_t *size,
  */
 void av_file_unmap(uint8_t *bufptr, size_t size);
 
+#if FF_API_AV_FOPEN_UTF8
 /**
  * Wrapper to work around the lack of mkstemp() on mingw.
  * Also, tries to create file in /tmp first, if possible.
@@ -67,6 +69,8 @@ void av_file_unmap(uint8_t *bufptr, size_t size);
  *       libraries and could interfere with the calling application.
  * @deprecated as fd numbers cannot be passed saftely between libs on some platforms
  */
+attribute_deprecated
 int av_tempfile(const char *prefix, char **filename, int log_offset, void *log_ctx);
+#endif
 
 #endif /* AVUTIL_FILE_H */

libavutil/version.h

@@ -79,7 +79,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR  57
-#define LIBAVUTIL_VERSION_MINOR  34
+#define LIBAVUTIL_VERSION_MINOR  35
 #define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \