CURLOPT_MAXREDIRS: allow -1 as a value

... which is valid according to documentation. Regression since
f121575c0b5f.

Verified now in test 501.

Reported-by: cbartl on github
Fixes #2038
Closes #2039

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/url.c b/lib/url.c
index dec402c1d..c334578ea 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -1043,7 +1043,7 @@ CURLcode Curl_setopt(struct Curl_easy *data, CURLoption option,
      * headers. This should mostly be used to detect never-ending loops.
      */
     arg = va_arg(param, long);
-    if(arg < 0)
+    if(arg < -1)
       return CURLE_BAD_FUNCTION_ARGUMENT;
     data->set.maxredirs = arg;
     break;