Teach winhttp about the extra headers

src/transports/winhttp.c

@@ -409,6 +409,23 @@ static int winhttp_stream_connect(winhttp_stream *s)
 		}
 	}
 
+	if (t->owner->custom_headers) {
+		for (i = 0; i < t->owner->custom_headers->count; i++) {
+			git_buf_clear(&buf);
+			git_buf_puts(&buf, t->owner->custom_headers->strings[i]);
+			if (git__utf8_to_16(ct, MAX_CONTENT_TYPE_LEN, git_buf_cstr(&buf)) < 0) {
+				giterr_set(GITERR_OS, "Failed to convert custom header to wide characters");
+				goto on_error;
+			}
+
+			if (!WinHttpAddRequestHeaders(s->request, ct, (ULONG)-1L,
+				WINHTTP_ADDREQ_FLAG_ADD | WINHTTP_ADDREQ_FLAG_REPLACE)) {
+				giterr_set(GITERR_OS, "Failed to add a header to the request");
+				goto on_error;
+			}
+		}
+	}
+
 	/* If requested, disable certificate validation */
 	if (t->connection_data.use_ssl) {
 		int flags;