Fix "check" mode warnings
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 53cfd09..afb896e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -15,7 +15,7 @@
 if(CMAKE_COMPILER_IS_CLANG)
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O2 -Wall -Wextra -W -Wdeclaration-after-statement")
   set(CMAKE_C_FLAGS_DEBUG "-g3 -O0")
-  set(CMAKE_C_FLAGS_CHECK "${CMAKE_C_FLAGS} -Werror -Wpointer-arith -Wwrite-strings -Wdocumentation -Wno-unused-function")
+  set(CMAKE_C_FLAGS_CHECK "${CMAKE_C_FLAGS} -Werror -Wpointer-arith -Wwrite-strings -Wdocumentation")
 endif(CMAKE_COMPILER_IS_CLANG)
 
 if(CMAKE_BUILD_TYPE STREQUAL "Coverage")
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index e430ae8..be93649 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -30,6 +30,7 @@
 endfunction(add_test_suite)
 
 set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-unused-function -Wno-unused-value")
+set(CMAKE_C_FLAGS_CHECK "${CMAKE_C_FLAGS_CHECK} -Wno-unused-function -Wno-unused-value")
 
 add_test_suite(aes aes.ecb)
 add_test_suite(aes aes.cbc)