--- ip2lib_d/Makefile.orig	2018-05-10 22:24:33.000000000 +0900
+++ ip2lib_d/Makefile	2019-11-29 15:29:31.000000000 +0900
@@ -24,7 +24,7 @@
 .SUFFIXES:
 .SUFFIXES: .F90 .f90 .o
 .F90.o:
-	$(FC) $(FFLAGS) ${FTN_REAL8} $(FPPFLAGS) $<
+	$(FC) $(FFLAGS) ${FTN_REAL8} $(FPPFLAGS) $< -c
 
 .f90.o:
-	$(FC) $(FFLAGS) ${FTN_REAL8} $<
+	$(FC) $(FFLAGS) ${FTN_REAL8} $< -c