Bug 1333686 - Part 2: Fix "unary minus operator applied to unsigned type" MSVC warnings in webrtc/signaling. r=bwc

Replace -1UL with ULONG_MAX.

media/webrtc/signaling/src/sdp/sipcc/sdp_attr.c(584): warning C4146: unary minus operator applied to unsigned type, result still unsigned
media/webrtc/signaling/src/sdp/sipcc/sdp_attr.c(585): warning C4146: unary minus operator applied to unsigned type, result still unsigned
media/webrtc/signaling/src/sdp/sipcc/sdp_attr.c(586): warning C4146: unary minus operator applied to unsigned type, result still unsigned

MozReview-Commit-ID: EepB2xf4MZr

--HG--
extra : rebase_source : 3a86d6b58f1ed1a852de1038dbb7c6e0694b2714

media/webrtc/signaling/src/sdp/sipcc/sdp_attr.c

@@ -581,9 +581,9 @@ sdp_result_e sdp_get_fmtp_tok_val(sdp_t *sdp_p,
 
   if (errno
       || (*tok == strtoul_end)
-      || (illegal_value != -1UL && value == illegal_value)
-      || (min_limit != -1UL && value < min_limit)
-      || (max_limit != -1UL && value > max_limit)) {
+      || (illegal_value != ULONG_MAX && value == illegal_value)
+      || (min_limit != ULONG_MAX && value < min_limit)
+      || (max_limit != ULONG_MAX && value > max_limit)) {
     sdp_attr_fmtp_invalid_value(sdp_p, fmtp_name, *tok);
     return SDP_INVALID_PARAMETER;
   }
@@ -592,7 +592,6 @@ sdp_result_e sdp_get_fmtp_tok_val(sdp_t *sdp_p,
   return SDP_SUCCESS;
 }
 
-
 sdp_result_e sdp_parse_attr_fmtp (sdp_t *sdp_p, sdp_attr_t *attr_p,
                                   const char *ptr)
 {