Made FlatBuffers compile correctly with -pedantic

Change-Id: I88b5993219e10e2dfb60ff98d6594d19871988fc
Tested: on Linux
diff --git a/CMakeLists.txt b/CMakeLists.txt
index be7bddd..de525e2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -52,14 +52,17 @@
 # source_group(Tests FILES ${FlatBuffers_Tests_SRCS})
 
 if(APPLE)
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -stdlib=libc++ -Wall")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -stdlib=libc++")
 elseif(CMAKE_COMPILER_IS_GNUCXX OR "${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++0x -Wall")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++0x")
 endif()
 
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -pedantic -Werror")
+
 if(FLATBUFFERS_CODE_COVERAGE)
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -fprofile-arcs -ftest-coverage")
-  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -fprofile-arcs -ftest-coverage")
+  set(CMAKE_EXE_LINKER_FLAGS
+      "${CMAKE_EXE_LINKER_FLAGS} -fprofile-arcs -ftest-coverage")
 endif()
 
 include_directories(include)