diff --git a/cmake/AwsCFlags.cmake b/cmake/AwsCFlags.cmake
--- a/cmake/AwsCFlags.cmake	(revision 4a21a1c0757083a16497fea27886f5f20ccdf334)
+++ b/cmake/AwsCFlags.cmake	(date 1618758078727)
@@ -70,9 +70,11 @@
 
        # -moutline-atomics generates code for both older load/store exclusive atomics and also
        # Arm's Large System Extensions (LSE) which scale substantially better on large core count systems
-        check_c_compiler_flag(-moutline-atomics HAS_MOUTLINE_ATOMICS)
-        if (HAS_MOUTLINE_ATOMICS)
-            list(APPEND AWS_C_FLAGS -moutline-atomics)
+        if(NOT EMSCRIPTEN AND NOT ANDROID)
+            check_c_compiler_flag(-moutline-atomics HAS_MOUTLINE_ATOMICS)
+            if (HAS_MOUTLINE_ATOMICS)
+                list(APPEND AWS_C_FLAGS -moutline-atomics)
+            endif()
         endif()
     endif()