+void avpriv_report_missing_feature(void *avc,
+ const char *msg, ...) av_printf_format(2, 3);
+
+/**
+ * Log a generic warning message about a missing feature.
+ * Additionally request that a sample showcasing the feature be uploaded.
+ *
+ * @param[in] avc a pointer to an arbitrary struct of which the first field is
+ * a pointer to an AVClass struct
+ * @param[in] msg string containing the name of the missing feature
+ */
+void avpriv_request_sample(void *avc,
+ const char *msg, ...) av_printf_format(2, 3);
+
+#if HAVE_LIBC_MSVCRT
+#include <crtversion.h>
+#if defined(_VC_CRT_MAJOR_VERSION) && _VC_CRT_MAJOR_VERSION < 14
+#pragma comment(linker, "/include:"EXTERN_PREFIX"avpriv_strtod")
+#pragma comment(linker, "/include:"EXTERN_PREFIX"avpriv_snprintf")
+#endif
+
+#define avpriv_open ff_open
+#endif
+
+/**
+ * A wrapper for open() setting O_CLOEXEC.
+ */
+int avpriv_open(const char *filename, int flags, ...);
+
+int avpriv_set_systematic_pal2(uint32_t pal[256], enum AVPixelFormat pix_fmt);