models: merge md5 mesh and anim on load

Merge content with use zero as separator
of content sections.

Fixes: https://github.com/yquake2/yquake2remaster/issues/4

src/client/refresh/files/models.c

@@ -1439,7 +1439,35 @@ Mod_LoadFileWithoutExt(const char *namewe, void **buffer, const char* ext)
 		filesize = ri.FS_LoadFile(newname, buffer);
 		if (filesize > 0)
 		{
-			return filesize;
+			int fullsize, filesize_anim;
+			char *final_buffer = NULL;
+			void *anim_buffer = NULL;
+
+			Q_strlcpy(newname, namewe, sizeof(newname));
+			Q_strlcat(newname, ".md5anim", sizeof(newname));
+			filesize_anim = ri.FS_LoadFile(newname, &anim_buffer);
+
+			if (filesize_anim <= 0)
+			{
+				return filesize;
+			}
+
+			fullsize = filesize + filesize_anim + 1;
+
+			/* allocate new buffer, ERR_FATAL on alloc fail */
+			final_buffer = ri.FS_AllocFile(fullsize);
+
+			/* copy combined information */
+			memcpy(final_buffer, *buffer, filesize);
+			final_buffer[filesize] = 0;
+			memcpy(final_buffer + filesize + 1, anim_buffer, filesize_anim);
+
+			/* Remove old buffers */
+			ri.FS_FreeFile(anim_buffer);
+			ri.FS_FreeFile(*buffer);
+
+			*buffer = final_buffer;
+			return fullsize;
 		}
 
 		/* Check Heretic2 model */

src/client/vid/header/ref.h

@@ -233,6 +233,7 @@ typedef struct
 	// NULL can be passed for buf to just determine existance
 	int		(IMPORT *FS_LoadFile) (const char *name, void **buf);
 	void	(IMPORT *FS_FreeFile) (void *buf);
+	void	*(IMPORT *FS_AllocFile) (int size);
 
 	// gamedir will be the current directory that generated
 	// files should be stored to, ie: "f:\quake\id1"

src/client/vid/vid.c

@@ -438,6 +438,7 @@ VID_LoadRenderer(void)
 	ri.FS_FreeFile = FS_FreeFile;
 	ri.FS_Gamedir = FS_Gamedir;
 	ri.FS_LoadFile = FS_LoadFile;
+	ri.FS_AllocFile = Z_Malloc;
 	ri.GLimp_InitGraphics = GLimp_InitGraphics;
 	ri.GLimp_GetDesktopMode = GLimp_GetDesktopMode;
 	ri.Sys_Error = Com_Error;