Make sure that Netlib LAPACK respects FFLAGS

OpenBLAS allows users to specify `FFLAGS` and then uses `override` to append additional
options. However, without such an override in lapack's make.inc, lapack would use the external
FFLAGS, rather than the ones being computed by OpenBLAS. For example the `DEBUG=1` flag
would not apply to LAPACK code. This is all a bit messy but forced by the integration with netlib
lapack. Note that `CFLAGS` already has this override for the same reason. It is possible that
other variables here should have a similar override, but I think for most of the other ones, OpenBLAS's
build system does not append to the flags passed in by the user.

Makefile

@@ -269,7 +269,7 @@ prof_lapack : lapack_prebuild
 lapack_prebuild :
 ifeq ($(NOFORTRAN), $(filter 0,$(NOFORTRAN)))
 	-@echo "FC          = $(FC)" > $(NETLIB_LAPACK_DIR)/make.inc
-	-@echo "FFLAGS      = $(LAPACK_FFLAGS)" >> $(NETLIB_LAPACK_DIR)/make.inc
+	-@echo "override FFLAGS      = $(LAPACK_FFLAGS)" >> $(NETLIB_LAPACK_DIR)/make.inc
 	-@echo "FFLAGS_DRV  = $(LAPACK_FFLAGS)" >> $(NETLIB_LAPACK_DIR)/make.inc
 	-@echo "POPTS       = $(LAPACK_FPFLAGS)" >> $(NETLIB_LAPACK_DIR)/make.inc
 	-@echo "FFLAGS_NOOPT       = -O0 $(LAPACK_NOOPT)" >> $(NETLIB_LAPACK_DIR)/make.inc