http: Use a constant for the supported header size

libavformat/http.c

@@ -529,7 +529,7 @@ static int http_connect(URLContext *h, const char *path, const char *local_path,
 {
     HTTPContext *s = h->priv_data;
     int post, err;
-    char headers[1024] = "";
+    char headers[HTTP_HEADERS_SIZE] = "";
     char *authstr = NULL, *proxyauthstr = NULL;
     int64_t off = s->off;
     int len = 0;

libavformat/http.h

@@ -24,6 +24,8 @@
 
 #include "url.h"
 
+#define HTTP_HEADERS_SIZE 1024
+
 /**
  * Initialize the authentication state based on another HTTP URLContext.
  * This can be used to pre-initialize the authentication parameters if