diff --git a/CMakeLists.txt b/CMakeLists.txt
index f0099cc90..5974b5c92 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -63,44 +63,33 @@ endif()
 #
 # Look for C library functions
 #
-set(CMAKE_EXTRA_INCLUDE_FILES string.h)
-check_function_exists(rawmemchr HAS_RAWMEMCHR)
-set(HAS_RAWMEMCHR ${HAS_RAWMEMCHR})
 
-set(CMAKE_EXTRA_INCLUDE_FILES stdlib.h)
-check_function_exists(reallocarray HAS_REALLOCARRAY)
-set(HAS_REALLOCARRAY ${HAS_REALLOCARRAY})
+set(CMAKE_EXTRA_INCLUDE_FILES
+	fcntl.h
+	stdlib.h
+	sys/socket.h
+	sys/types.h
+	string.h
+	time.h
+	unistd.h
+)
+set(CMAKE_REQUIRED_LIBRARIES ${CMAKE_THREAD_LIBS_INIT})
 
+check_function_exists(rawmemchr HAS_RAWMEMCHR)
+check_function_exists(reallocarray HAS_REALLOCARRAY)
 check_function_exists(mempcpy HAS_MEMPCPY)
-set(HAS_MEMPCPY ${HAS_MEMPCPY})
-
 check_function_exists(memrchr HAS_MEMRCHR)
-set(HAS_MEMRCHR ${HAS_MEMRCHR})
-
-set(CMAKE_EXTRA_INCLUDE_FILES unistd.h)
 check_function_exists(pipe2 HAS_PIPE2)
-set(HAS_PIPE2 ${HAS_PIPE2})
-
-set(CMAKE_EXTRA_INCLUDE_FILES sys/types.h sys/socket.h)
 check_function_exists(accept4 HAS_ACCEPT4)
-set(HAS_ACCEPT4 ${HAS_ACCEPT4})
-
-set(CMAKE_EXTRA_INCLUDE_FILES fcntl.h)
 check_function_exists(readahead HAS_READAHEAD)
-set(HAS_READAHEAD ${HAS_READAHEAD})
-
 check_function_exists(mkostemp HAS_MKOSTEMP)
-set(HAS_MKOSTEMP ${HAS_MKOSTEMP})
-
-set(CMAKE_EXTRA_INCLUDE_FILES time.h)
 check_function_exists(clock_gettime HAS_CLOCK_GETTIME)
+check_function_exists(pthread_barrier_init HAS_PTHREADBARRIER)
+
 if (NOT HAS_CLOCK_GETTIME AND ${CMAKE_SYSTEM_NAME} MATCHES "Linux")
 	list(APPEND ADDITIONAL_LIBRARIES rt)
 endif ()
 
-set(CMAKE_REQUIRED_LIBRARIES ${CMAKE_THREAD_LIBS_INIT})
-check_function_exists(pthread_barrier_init HAS_PTHREADBARRIER)
-
 
 #
 # Ensure compiler is compatible with GNU99 standard