- pass external FFLAGS to the build

--- CMakeLists.txt.orig	2022-07-17 04:43:42 UTC
+++ CMakeLists.txt
@@ -11,7 +11,7 @@ endif()
 
 # sometimes cmake clears CMAKE_Fortran_FLAGS during project()
 set(CMAKE_Fortran_FLAGS_backup ${CMAKE_Fortran_FLAGS})
-set(CMAKE_Fortran_FLAGS "")
+#set(CMAKE_Fortran_FLAGS "")
 project(FLEUR LANGUAGES C CXX Fortran)
 string(STRIP "${CMAKE_Fortran_FLAGS} ${CMAKE_Fortran_FLAGS_backup}" CMAKE_Fortran_FLAGS)
 
