diff --git a/cmake/arch.cmake b/cmake/arch.cmake
index c00f8fe71..c048f13d1 100644
--- a/cmake/arch.cmake
+++ b/cmake/arch.cmake
@@ -1,4 +1,3 @@
-##
 ## Author: Hank Anderson <hank@statease.com>
 ## Description: Ported from portion of OpenBLAS/Makefile.system
 ##              Sets various variables based on architecture.
@@ -80,10 +79,15 @@ if (DYNAMIC_ARCH)
       string(REGEX REPLACE "-march=native" "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
     endif ()
     if (DYNAMIC_LIST)
-	set(DYNAMIC_CORE PRESCOTT ${DYNAMIC_LIST})
+      set(DYNAMIC_CORE PRESCOTT ${DYNAMIC_LIST})
     endif ()
   endif ()
 
+  CHECK_INCLUDE_FILE ("${PROJECT_SOURCE_DIR}/config_kernel.h" TRAP)
+  if (TRAP)
+	  message (FATAL_ERROR "Your build directory contains a file config_kernel.h, probably from a previous compilation with make. This will conflict with the cmake compilation and cause strange compiler errors - please remove the file before trying again")
+  endif ()
+
   if (NOT DYNAMIC_CORE)
     message (STATUS "DYNAMIC_ARCH is not supported on this architecture, removing from options")
     unset(DYNAMIC_ARCH CACHE)
diff --git a/cmake/system_check.cmake b/cmake/system_check.cmake
index d06f4779f..b0ab926fc 100644
--- a/cmake/system_check.cmake
+++ b/cmake/system_check.cmake
@@ -121,7 +121,6 @@ endif()
 
 include(CheckIncludeFile)
 CHECK_INCLUDE_FILE("stdatomic.h" HAVE_C11)
-if (HAVE_C11 EQUAL 1)
-message (STATUS found stdatomic.h)
+if (HAVE_C11)
 set (CCOMMON_OPT "${CCOMMON_OPT} -DHAVE_C11")
 endif()