diff --git a/build/gyp.mozbuild b/build/gyp.mozbuild
index a78289b0c448..764023648bcd 100644
--- a/build/gyp.mozbuild
+++ b/build/gyp.mozbuild
@@ -26,6 +26,7 @@ gyp_vars.update({
     # basic stuff for everything
     'include_internal_video_render': 0,
     'clang': 1 if CONFIG['CC_TYPE'] == 'clang' else 0,
+    'clang_cl': 1 if CONFIG['CC_TYPE'] == 'clang-cl' else 0,
     'clang_use_chrome_plugins': 0,
     'enable_protobuf': 0,
     'include_tests': 0,
diff --git a/media/mtransport/third_party/nICEr/nicer.gyp b/media/mtransport/third_party/nICEr/nicer.gyp
index 3f61939eb432..3ce6cc627021 100644
--- a/media/mtransport/third_party/nICEr/nicer.gyp
+++ b/media/mtransport/third_party/nICEr/nicer.gyp
@@ -204,8 +204,20 @@
                  ],
               }],
 
+              # Windows, clang-cl build
+              [ 'clang_cl == 1', {
+                'cflags_mozilla': [
+                    '-Wall',
+                    '-Wno-parentheses',
+                    '-Wno-strict-prototypes',
+                    '-Wmissing-prototypes',
+                    '-Wno-format',
+                    '-Wno-format-security',
+                 ],
+              }],
+
               ## Linux/Android
-              [ '(OS == "linux") or (OS=="android")', {
+              [ '(OS == "linux") or (OS == "android")', {
                 'cflags_mozilla': [
                     '-Wall',
                     '-Wno-parentheses',
diff --git a/media/mtransport/third_party/nrappkit/nrappkit.gyp b/media/mtransport/third_party/nrappkit/nrappkit.gyp
index 655122ce697d..844c9987c4a9 100644
--- a/media/mtransport/third_party/nrappkit/nrappkit.gyp
+++ b/media/mtransport/third_party/nrappkit/nrappkit.gyp
@@ -201,6 +201,18 @@
                  ],
               }],
 
+              # Windows, clang-cl build
+              [ 'clang_cl == 1', {
+                'cflags_mozilla': [
+                    '-Wall',
+                    '-Wno-parentheses',
+                    '-Wno-strict-prototypes',
+                    '-Wmissing-prototypes',
+                    '-Wno-format',
+                    '-Wno-format-security',
+                 ],
+              }],
+
               ## Linux/Android
               [ '(OS == "linux") or (OS == "android")', {
                  'cflags_mozilla': [