diff --git a/unix/hlib/d1mach.f b/unix/hlib/d1mach.f
index ccecd10..e915e45 100644
--- a/unix/hlib/d1mach.f
+++ b/unix/hlib/d1mach.f
@@ -33,11 +33,16 @@ C
 C  COMMENTS JUST BEFORE THE END STATEMENT (LINES STARTING WITH *)
 C  GIVE C SOURCE FOR D1MACH.
 C
-      INTEGER SMALL(2)
-      INTEGER LARGE(2)
-      INTEGER RIGHT(2)
-      INTEGER DIVER(2)
-      INTEGER LOG10(2)
+C Need to explcitly put in integer size to work on GFORTRAN with
+C -fdefault-integer-4.
+C
+C See http://comments.gmane.org/gmane.comp.gcc.bugs/189700
+C For details
+      INTEGER(4) SMALL(2)
+      INTEGER(4) LARGE(2)
+      INTEGER(4) RIGHT(2)
+      INTEGER(4) DIVER(2)
+      INTEGER(4) LOG10(2)
       INTEGER I
 C/6S
 C/7S
diff --git a/unix/hlib/irafuser.csh b/unix/hlib/irafuser.csh
index cf6d4d5..3c706e9 100644
--- a/unix/hlib/irafuser.csh
+++ b/unix/hlib/irafuser.csh
@@ -71,12 +71,18 @@ case ipad:
     set    mkzflags = "'lflags=-z'"
     breaksw
 
+# The default-integer-8 is very important to make everything compatible
+# with f2c which defines integer as long
 case linux64:
+    setenv F77 gfortran
+    setenv XC_F77 gfortran
+    setenv XC_FFLAGS -fdefault-integer-8
+    setenv XC_LFLAGS -lgfortran
     setenv HSI_CF "-g -O2 -I/usr/include -I${hlib}libc -DLINUX -DREDHAT -DPOSIX -DSYSV -DLINUX64 -DMACH64 -w -m64 -DNOLIBCNAMES -DHOST_F2C -DHOST_CURL -DHOST_EXPAT"
-    setenv HSI_XF "-g -Inolibc -I${hlib}libc -w -/m64 -/Wunused"
-    setenv HSI_FF "-g -m64 -DBLD_KERNEL"
-    setenv HSI_LF "-m64 "
-    setenv HSI_F77LIBS ""
+    setenv HSI_XF "-g -O2 -Inolibc -I${hlib}libc -w -/m64 -/Wunused"
+    setenv HSI_FF "-g -O2 -m64 -DBLD_KERNEL -fdefault-integer-8"
+    setenv HSI_LF "-m64 -fdefault-integer-8"
+    setenv HSI_F77LIBS "-lgfortran"
     setenv HSI_LFLAGS ""
     setenv HSI_OSLIBS ""
     set    mkzflags = "'lflags=-Nxz -/Wl,-Bstatic'"
@@ -84,11 +90,13 @@ case linux64:
 
 case linux:
 case redhat:
+    setenv F77 gfortran
+    setenv XC_F77 gfortran
     setenv HSI_CF "-g -O2 -I/usr/include -I${hlib}libc -DLINUX -DREDHAT -DPOSIX -DSYSV -w -m32 -Wunused -DHOST_F2C -DHOST_CURL -DHOST_EXPAT -DHOST_XMLRPC"
     setenv HSI_XF "-Inolibc -I${hlib}libc -w -/Wunused -/m32"
     setenv HSI_FF "-O -DBLD_KERNEL -m32"
     setenv HSI_LF "-m32"
-    setenv HSI_F77LIBS ""
+    setenv HSI_F77LIBS "-lgfortran"
     setenv HSI_LFLAGS ""
     setenv HSI_OSLIBS ""
     set    mkzflags = "'lflags=-Nxz -/Wl,-Bstatic'"
@@ -140,7 +148,7 @@ setenv HSI_XF  "-I${HOME}/.iraf/ $HSI_XF"
 # The following determines whether or not the VOS is used for filename mapping.
 if (-f ${iraf}lib/libsys.a) then
 	setenv	HSI_LIBS\
-    "${hbin}libboot.a ${iraf}lib/libsys.a ${iraf}lib/libvops.a -lf2c ${hbin}libos.a"
+    "${hbin}libboot.a ${iraf}lib/libsys.a ${iraf}lib/libvops.a ${hbin}libos.a -lm -lgfortran"
 else
 	setenv	HSI_CF "$HSI_CF -DNOVOS"
 	setenv	HSI_LIBS "${hbin}libboot.a ${hbin}libos.a"
diff --git a/unix/hlib/r1mach.f b/unix/hlib/r1mach.f
index 167e19f..e387fab 100644
--- a/unix/hlib/r1mach.f
+++ b/unix/hlib/r1mach.f
@@ -29,11 +29,17 @@ C
 C  COMMENTS JUST BEFORE THE END STATEMENT (LINES STARTING WITH *)
 C  GIVE C SOURCE FOR R1MACH.
 C
-      INTEGER SMALL(2)
-      INTEGER LARGE(2)
-      INTEGER RIGHT(2)
-      INTEGER DIVER(2)
-      INTEGER LOG10(2)
+C Need to explcitly put in integer size to work on GFORTRAN with
+C -fdefault-integer-4.
+C
+C See http://comments.gmane.org/gmane.comp.gcc.bugs/189700
+C For details
+
+      INTEGER(4) SMALL(2)
+      INTEGER(4) LARGE(2)
+      INTEGER(4) RIGHT(2)
+      INTEGER(4) DIVER(2)
+      INTEGER(4) LOG10(2)
       INTEGER I
 C/6S
 C/7S