diff -uNr geant4.7.1.p01.ORIG/config/sys/Darwin-g++.gmk geant4.7.1.p01/config/sys/Darwin-g++.gmk
--- geant4.7.1.p01.ORIG/config/sys/Darwin-g++.gmk	2005-10-25 16:13:16.000000000 +0900
+++ geant4.7.1.p01/config/sys/Darwin-g++.gmk	2005-11-14 14:25:28.000000000 +0900
@@ -29,9 +29,15 @@
     FCFLAGS   += -pg
     CCFLAGS   += -pg
   endif
-  FC := g77
-  FCFLAGS += -fno-automatic -fno-backslash -fno-second-underscore
-  FCLIBS := -lg2c -lnsl
+  ifeq ($(shell which gfortran | grep -c 'no gfortran'),0)
+    FC := gfortran
+    FCFLAGS += -fno-automatic -fno-backslash -fno-second-underscore
+    FCLIBS := -lgfortran -lgfortranbegin -lnsl
+  else
+    FC := g77
+    FCFLAGS += -fno-automatic -fno-backslash -fno-second-underscore
+    FCLIBS := -lg2c -lnsl
+  endif
   ECHO    := /bin/echo -n
   SHEXT   := dylib
   X11FLAGS  := -I/usr/include/X11/extensions -I/usr/include/X11
diff -uNr geant4.7.1.p01.ORIG/config/sys/Linux-g++.gmk geant4.7.1.p01/config/sys/Linux-g++.gmk
--- geant4.7.1.p01.ORIG/config/sys/Linux-g++.gmk	2005-10-25 16:13:16.000000000 +0900
+++ geant4.7.1.p01/config/sys/Linux-g++.gmk	2005-11-14 14:25:28.000000000 +0900
@@ -37,9 +37,17 @@
   endif
   G4RUNPATHOPTION := -Wl,-rpath 
   CC := gcc
-  FC := g77
-  FCFLAGS += -fno-automatic -fno-backslash -fno-second-underscore
-  FCLIBS := -lg2c -lnsl
+
+  ifeq ($(shell which gfortran | grep -c 'no gfortran'),0)
+    FC := gfortran
+    FCFLAGS += -fno-automatic -fno-backslash -fno-second-underscore
+    FCLIBS := -lgfortran -lgfortranbegin -lnsl
+  else
+    FC := g77
+    FCFLAGS += -fno-automatic -fno-backslash -fno-second-underscore
+    FCLIBS := -lg2c -lnsl
+  endif
+
   ECHO    := /bin/echo -e
   SHEXT   := so
   X11FLAGS  := -I/usr/include/X11/extensions -I/usr/include/X11