Update CMakeLists.txt

CMakeLists.txt

@@ -65,10 +65,16 @@ if (CMAKE_Fortran_COMPILER_ID STREQUAL "GNU")
     endif()
 elseif ((CMAKE_Fortran_COMPILER_ID STREQUAL "NVHPC") OR (CMAKE_Fortran_COMPILER_ID STREQUAL "PGI"))
     if (CMAKE_Fortran_COMPILER_VERSION VERSION_LESS 21.7)
-        message(FATAL_ERROR "${__err_msg}ERROR: NVHPC v21.7 or newer is required to build MFC.")
+        message(FATAL_ERROR "${__err_msg}ERROR: When using NVHPC, v21.7 or newer is required to build MFC.")
     endif()
-    if ((CMAKE_Fortran_COMPILER_VERSION VERSION_LESS 23.0) AND (MAKE_BUILD_TYPE STREQUAL "Debug") AND (MFC_OpenACC))
-        message(FATAL_ERROR "${__err_msg}ERROR: NVHPC v23.0 or newer is required to build MFC with GPU and Debug options.")
+    if (MAKE_BUILD_TYPE STREQUAL "Debug"))
+        if (MFC_OpenACC)
+            if (CMAKE_Fortran_COMPILER_VERSION VERSION_LESS 23.0))
+                message(FATAL_ERROR "${__err_msg}ERROR: When using NVHPC, v23.0 or newer is required to build MFC with Debug and GPU options.")
+            endif()
+        else()
+            message(FATAL_ERROR "${__err_msg}ERROR: Debug is not working with NVHPC and CPU options at present.")
+        endif()
     endif()
 elseif (CMAKE_Fortran_COMPILER_ID STREQUAL "AppleClang" OR CMAKE_C_COMPILER_ID STREQUAL "AppleClang")
     message(FATAL_ERROR "${__err_msg}ERROR: MFC does not support the Apple Clang compilers. Please consult the documentation.")