diff --git a/glslang/OSDependent/Web/CMakeLists.txt b/glslang/OSDependent/Web/CMakeLists.txt
index 6232b809..5d174960 100644
--- a/glslang/OSDependent/Web/CMakeLists.txt
+++ b/glslang/OSDependent/Web/CMakeLists.txt
@@ -67,18 +67,28 @@ if(ENABLE_GLSLANG_JS)
         endif()
 
         if(NOT ENABLE_EMSCRIPTEN_ENVIRONMENT_NODE)
-            if (CMAKE_HOST_SYSTEM MATCHES "Windows.*")
-                # There are several ways we could append one file to another on Windows, but unfortunately 'cat' is not one of them
-                # (there is no 'cat' command in cmd). Also, since this will ultimately run in cmd and not pwsh, we need to ensure
-                # Windows path separators are used.
-                file(TO_NATIVE_PATH "${CMAKE_CURRENT_BINARY_DIR}/glslang.js" glslang_js_path)
-                file(TO_NATIVE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/glslang.after.js" glslang_after_js_path)
+            if (CMAKE_VERSION VERSION_GREATER_EQUAL "3.18")
                 add_custom_command(TARGET glslang.js POST_BUILD
-                    COMMAND type "${glslang_after_js_path}" >> "${glslang_js_path}")
+                    COMMAND ${CMAKE_COMMAND} -E cat ${CMAKE_CURRENT_SOURCE_DIR}/glslang.after.js >> ${CMAKE_CURRENT_BINARY_DIR}/glslang.js
+                )
             else()
-                add_custom_command(TARGET glslang.js POST_BUILD
-                    COMMAND cat ${CMAKE_CURRENT_SOURCE_DIR}/glslang.after.js >> ${CMAKE_CURRENT_BINARY_DIR}/glslang.js)
+                if (MINGW)
+                    message(FATAL_ERROR "Must use at least CMake 3.18")
+                endif()
+
+                if (CMAKE_HOST_SYSTEM MATCHES "Windows.*")
+                    # There are several ways we could append one file to another on Windows, but unfortunately 'cat' is not one of them
+                    # (there is no 'cat' command in cmd). Also, since this will ultimately run in cmd and not pwsh, we need to ensure
+                    # Windows path separators are used.
+                    file(TO_NATIVE_PATH "${CMAKE_CURRENT_BINARY_DIR}/glslang.js" glslang_js_path)
+                    file(TO_NATIVE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/glslang.after.js" glslang_after_js_path)
+                    add_custom_command(TARGET glslang.js POST_BUILD
+                        COMMAND type "${glslang_after_js_path}" >> "${glslang_js_path}")
+                else()
+                    add_custom_command(TARGET glslang.js POST_BUILD
+                        COMMAND cat ${CMAKE_CURRENT_SOURCE_DIR}/glslang.after.js >> ${CMAKE_CURRENT_BINARY_DIR}/glslang.js)
+                endif()
             endif()
         endif()
     endif()
-endif()
+endif()
\ No newline at end of file