diff --git a/CMakeLists.txt b/CMakeLists.txt
index cd71a47..d92aed0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -53,8 +53,10 @@ if(MSVC)
   add_definitions(-D_HAS_EXCEPTIONS=0)
 
   # Disable RTTI.
+  if(NOT SNAPPY_WITH_RTTI)
   string(REGEX REPLACE "/GR" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /GR-")
+  endif()
 else(MSVC)
   # Use -Wall for clang and gcc.
   if(NOT CMAKE_CXX_FLAGS MATCHES "-Wall")
@@ -82,9 +84,11 @@ else(MSVC)
   string(REGEX REPLACE "-fexceptions" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-exceptions")
 
+  if(NOT SNAPPY_WITH_RTTI)
   # Disable RTTI.
   string(REGEX REPLACE "-frtti" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-rtti")
+  endif()
 endif(MSVC)
 
 # BUILD_SHARED_LIBS is a standard CMake variable, but we declare it here to make