remote-curl: unbreak http.extraHeader with custom allocators

In 93b980e (http: use xmalloc with cURL, 2019-08-15), we started to
ask cURL to use `xmalloc()`, and if compiled with nedmalloc, that means
implicitly a different allocator than the system one.

Which means that all of cURL's allocations and releases now _need_ to
use that allocator.

However, the `http_options()` function used `slist_append()` to add any
configured extra HTTP header(s) _before_ asking cURL to use `xmalloc()`,
and `http_cleanup()` would release them _afterwards_, i.e. in the
presence of custom allocators, cURL would attempt to use the wrong
allocator to release the memory.

Let's fix this by moving the initialization _before_ the
`http_options()` function is called.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

http.c

@@ -1064,6 +1064,9 @@ void http_init(struct remote *remote, const char *url, int proactive_auth)
 	char *normalized_url;
 	struct urlmatch_config config = { STRING_LIST_INIT_DUP };
 
+	if (curl_global_init(CURL_GLOBAL_ALL) != CURLE_OK)
+		die("curl_global_init failed");
+
 	config.section = "http";
 	config.key = NULL;
 	config.collect_fn = http_options;
@@ -1104,9 +1107,6 @@ void http_init(struct remote *remote, const char *url, int proactive_auth)
 	}
 #endif
 
-	if (curl_global_init(CURL_GLOBAL_ALL) != CURLE_OK)
-		die("curl_global_init failed");
-
 	http_proactive_auth = proactive_auth;
 
 	if (remote && remote->http_proxy)