--- a/src/third_party/mozjs/SConscript
+++ b/src/third_party/mozjs/SConscript
@@ -144,10 +143,6 @@
     "extract/js/src/wasm/WasmCode-platform.cpp",
 ]
 
-if env['TARGET_ARCH'] == 'x86_64' and not env.TargetOSIs('windows'):
-    env.Append(CCFLAGS=['-mavx2'])
-    sources.extend(["extract/mozglue/misc/SIMD_avx2.cpp", "extract/mozglue/misc/SSE.cpp"])
-
 if env.TargetOSIs('windows'):
     sources.extend([
         "extract/mozglue/misc/ConditionVariable_windows.cpp",