--- a/ipc/chromium/src/base/compiler_specific.h
+++ b/ipc/chromium/src/base/compiler_specific.h
@@ -62,20 +62,18 @@
 #define MSVC_PUSH_WARNING_LEVEL(n)
 #define MSVC_POP_WARNING()
 #define MSVC_DISABLE_OPTIMIZE()
 #define MSVC_ENABLE_OPTIMIZE()
 #define ALLOW_THIS_IN_INITIALIZER_LIST(code) code
 
 #endif  // COMPILER_MSVC
 
-// Annotate a function indicating the caller must examine the return value.
-// Use like:
-//   int foo() WARN_UNUSED_RESULT;
-// To explicitly ignore a result, see |ignore_result()| in base/macros.h.
-#undef WARN_UNUSED_RESULT
-#if defined(COMPILER_GCC) || defined(__clang__)
+
+#if defined(COMPILER_GCC)
+#define ALLOW_UNUSED __attribute__((unused))
 #define WARN_UNUSED_RESULT __attribute__((warn_unused_result))
-#else
+#else  // Not GCC
+#define ALLOW_UNUSED
 #define WARN_UNUSED_RESULT
 #endif
 
 #endif  // BASE_COMPILER_SPECIFIC_H_

--- a/media/webrtc/moz.build
+++ b/media/webrtc/moz.build
@@ -88,16 +88,17 @@ if CONFIG['MOZ_WEBRTC_SIGNALING']:
         'signaling/src/sdp/sipcc/sdp_base64.c',
         'signaling/src/sdp/sipcc/sdp_config.c',
         'signaling/src/sdp/sipcc/sdp_main.c',
         'signaling/src/sdp/sipcc/sdp_services_unix.c',
         'signaling/src/sdp/sipcc/sdp_token.c',
         'signaling/src/sdp/sipcc/sdp_utils.c',
     ]
 
+    GYP_DIRS['signaling'].sandbox_vars['ALLOW_COMPILER_WARNINGS'] = True
     GYP_DIRS['signaling'].non_unified_sources += signaling_non_unified_sources
 
     if CONFIG['_MSC_VER']:
         # Avoid warnings from third-party code that we can not modify.
         if CONFIG['CLANG_CL']:
             CXXFLAGS += ['-Wno-invalid-source-encoding']
         else:
             CXXFLAGS += ['-validate-charset-']
@@ -115,13 +116,13 @@ if CONFIG['MOZ_WIDGET_TOOLKIT'] != 'gonk
         GYP_DIRS += ['signalingtest']
         GYP_DIRS['signalingtest'].input = 'signaling/signaling.gyp'
         GYP_DIRS['signalingtest'].variables = gyp_vars.copy()
         GYP_DIRS['signalingtest'].variables.update(
             build_for_test=1,
             moz_webrtc_mediacodec=0,
             build_for_standalone=0
         )
-
+        GYP_DIRS['signalingtest'].sandbox_vars['ALLOW_COMPILER_WARNINGS'] = True
         GYP_DIRS['signalingtest'].non_unified_sources += signaling_non_unified_sources
 
 if CONFIG['ENABLE_TESTS']:
     DIRS += ['signaling/fuzztest']

--- a/media/webrtc/signaling/signaling.gyp
+++ b/media/webrtc/signaling/signaling.gyp
@@ -360,21 +360,16 @@
             'SIP_OS_OSX',
             'OSX',
             '_FORTIFY_SOURCE=2',
           ],
 
           'cflags_mozilla': [
           ],
         }],
-        ['clang == 1', {
-          'cflags_mozilla': [
-            '-Wno-inconsistent-missing-override',
-         ],
-        }],
       ],
     },
   ],
 }
 
 # Local Variables:
 # tab-width:2
 # indent-tabs-mode:nil

--- a/media/webrtc/signaling/src/jsep/JsepSessionImpl.cpp
+++ b/media/webrtc/signaling/src/jsep/JsepSessionImpl.cpp
@@ -317,21 +317,16 @@ JsepSessionImpl::SetParameters(const std
                                                                        | it->mTrack->GetDirection());
           break;
         }
         case SdpMediaSection::kAudio: {
           addAudioExt = static_cast<SdpDirectionAttribute::Direction>(addAudioExt
                                                                       | it->mTrack->GetDirection());
           break;
         }
-        case SdpMediaSection::kApplication:
-        case SdpMediaSection::kMessage:
-        case SdpMediaSection::kText:
-          MOZ_ASSERT_UNREACHABLE("Unexpected track MediaType");
-          break;
       }
     }
   }
   if (addVideoExt != SdpDirectionAttribute::kInactive) {
     AddVideoRtpExtension("urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id", addVideoExt);
   }
   if (addAudioExt != SdpDirectionAttribute::kInactive) {
     AddAudioRtpExtension("urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id", addAudioExt);

--- a/media/webrtc/signaling/src/sdp/sipcc/sdp_attr.c
+++ b/media/webrtc/signaling/src/sdp/sipcc/sdp_attr.c
@@ -576,27 +576,28 @@ sdp_result_e sdp_get_fmtp_tok_val(sdp_t 
   result1 = sdp_get_fmtp_tok(sdp_p, fmtp_ptr, fmtp_name, buf, buf_size, tok);
   if (result1 != SDP_SUCCESS) return result1;
 
   errno = 0;
   value = strtoul(*tok, &strtoul_end, 10);
 
   if (errno
       || (*tok == strtoul_end)
-      || (illegal_value != ULONG_MAX && value == illegal_value)
-      || (min_limit != ULONG_MAX && value < min_limit)
-      || (max_limit != ULONG_MAX && value > max_limit)) {
+      || (illegal_value != -1UL && value == illegal_value)
+      || (min_limit != -1UL && value < min_limit)
+      || (max_limit != -1UL && value > max_limit)) {
     sdp_attr_fmtp_invalid_value(sdp_p, fmtp_name, *tok);
     return SDP_INVALID_PARAMETER;
   }
   *strtoul_result = value;
 
   return SDP_SUCCESS;
 }
 
+
 sdp_result_e sdp_parse_attr_fmtp (sdp_t *sdp_p, sdp_attr_t *attr_p,
                                   const char *ptr)
 {
     uint16_t           i;
     uint32_t           mapword;
     uint32_t           bmap;
     uint8_t            low_val;
     uint8_t            high_val;