diff --git a/native/wasm/build.cake b/native/wasm/build.cake
index 91e0082a2f..cfa51de6de 100644
--- a/native/wasm/build.cake
+++ b/native/wasm/build.cake
@@ -63,7 +63,7 @@ Task("libSkiaSharp")
         $"  '-s', 'WARN_UNALIGNED=1' " + // '-s', 'USE_WEBGL2=1' (experimental)
         $"] " +
         // SIMD support is based on https://github.com/google/skia/blob/1f193df9b393d50da39570dab77a0bb5d28ec8ef/modules/canvaskit/compile.sh#L57
-        $"extra_cflags_cc=[ '-frtti' { (hasSimdEnabled ? ", '-msimd128'" : "") { (hasThreadingEnabled ? ", '-pthread'" : "") } } ] " +
+        $"extra_cflags_cc=[ '-frtti' { (hasSimdEnabled ? ", '-msimd128'" : "") } { (hasThreadingEnabled ? ", '-pthread'" : "") } ] " +
         COMPILERS +
         ADDITIONAL_GN_ARGS);
 
@@ -107,12 +107,15 @@ Task("libHarfBuzzSharp")
     .WithCriteria(IsRunningOnLinux())
     .Does(() =>
 {
+    bool hasSimdEnabled = EMSCRIPTEN_FEATURES.Contains("simd");
+    bool hasThreadingEnabled = EMSCRIPTEN_FEATURES.Contains("mt");
+
     GnNinja($"wasm", "HarfBuzzSharp",
         $"target_os='linux' " +
         $"target_cpu='wasm' " +
         $"is_static_skiasharp=true " +
         $"visibility_hidden=false " +
-        $"extra_cflags_cc=[ '-frtti' { (hasSimdEnabled ? ", '-msimd128'" : "") { (hasThreadingEnabled ? ", '-pthread'" : "") } } ] " +
+        $"extra_cflags_cc=[ '-frtti' { (hasSimdEnabled ? ", '-msimd128'" : "") } { (hasThreadingEnabled ? ", '-pthread'" : "") } ] " +
         COMPILERS +
         ADDITIONAL_GN_ARGS);