Adjust warnings in different modes
diff --git a/library/CMakeLists.txt b/library/CMakeLists.txt
index 33d96b4..f562ca6 100644
--- a/library/CMakeLists.txt
+++ b/library/CMakeLists.txt
@@ -78,12 +78,11 @@
 endif(WIN32)
 
 if(CMAKE_COMPILER_IS_GNUCC)
-  set(CMAKE_C_FLAGS_CHECK "${CMAKE_C_FLAGS_CHECK} -Wmissing-declarations -Wmissing-prototypes")
-  set(CMAKE_C_FLAGS_CHECKFULL "${CMAKE_C_FLAGS_CHECK} -Wcast-qual")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wmissing-declarations -Wmissing-prototypes")
 endif(CMAKE_COMPILER_IS_GNUCC)
 
 if(CMAKE_COMPILER_IS_CLANG)
-  set(CMAKE_C_FLAGS_CHECK "${CMAKE_C_FLAGS_CHECK} -Wmissing-declarations -Wmissing-prototypes")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wmissing-declarations -Wmissing-prototypes -Wdocumentation -Wunreachable-code")
 endif(CMAKE_COMPILER_IS_CLANG)
 
 if (NOT USE_STATIC_POLARSSL_LIBRARY AND NOT USE_SHARED_POLARSSL_LIBRARY)