diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 11f9ebabf3..f6740420b7 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -136,6 +136,10 @@ else()
         -Wno-unused-parameter
         -Wno-missing-field-initializers
     )
+    # iOS clang doesn't like this specific option
+    if (NOT IOS)
+        add_compile_options(-Werror=missing-declarations)
+    endif()
 
     if (CXX_CLANG OR CXX_ICC OR CXX_APPLE) # Clang, AppleClang, or Intel C++
         if (NOT MSVC)