Filter out FFLAGS that flang-new from LLVM18 no longer supports

Makefile.system

@@ -1670,6 +1670,10 @@ ifeq ($(F_COMPILER),CRAY)
 LAPACK_FFLAGS := $(filter-out -msse3 -mssse3 -msse4.1 -mavx -mavx2 -mskylake-avx512 ,$(FFLAGS))
 override FFLAGS := $(filter-out -msse3 -mssse3 -msse4.1 -mavx -mavx2 -mskylake-avx512 ,$(FFLAGS))
 endif
+ifeq ($(F_COMPILER),FLANGNEW)
+LAPACK_FFLAGS := $(filter-out -m32 -m64 -msse3 -mssse3 -msse4.1 -mavx -mavx2 -mskylake-avx512 ,$(FFLAGS))
+override FFLAGS := $(filter-out -m32 -m64 -msse3 -mssse3 -msse4.1 -mavx -mavx2 -mskylake-avx512 ,$(FFLAGS))
+endif
 
 LAPACK_CFLAGS = $(CFLAGS)
 LAPACK_CFLAGS += -DHAVE_LAPACK_CONFIG_H