Index: src/third_party/mozjs/SConscript
--- src/third_party/mozjs/SConscript.orig
+++ src/third_party/mozjs/SConscript
@@ -147,7 +147,7 @@ sources = [
     "extract/js/src/wasm/WasmCode-platform.cpp",
 ]
 
-if env['TARGET_ARCH'] == 'x86_64' and not env.TargetOSIs('windows'):
+if False and 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"])
 
