)hwcontext: add a stub implementation for Vulkan functions

libavutil/Makefile

@@ -196,6 +196,8 @@ OBJS-$(CONFIG_VIDEOTOOLBOX)             += hwcontext_videotoolbox.o
 OBJS-$(CONFIG_VDPAU)                    += hwcontext_vdpau.o
 OBJS-$(CONFIG_VULKAN)                   += hwcontext_vulkan.o
 
+OBJS-$(!CONFIG_VULKAN)                  += hwcontext_stub.o
+
 OBJS += $(COMPAT_OBJS:%=../compat/%)
 
 # Windows resource file

libavutil/hwcontext_stub.c

@@ -0,0 +1,39 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "config.h"
+
+#if !CONFIG_VULKAN
+#include <stddef.h>
+#include "pixfmt.h"
+
+typedef enum VkFormat VkFormat;
+typedef struct AVVkFrame AVVkFrame;
+const VkFormat *av_vkfmt_from_pixfmt(enum AVPixelFormat p);
+AVVkFrame *av_vk_frame_alloc(void);
+
+const VkFormat *av_vkfmt_from_pixfmt(enum AVPixelFormat p)
+{
+    return NULL;
+}
+
+AVVkFrame *av_vk_frame_alloc(void)
+{
+    return NULL;
+}
+#endif /* CONFIG_VULKAN */