head no longer supports "-1" syntax

Index: dtn-2.5.0/oasys/aclocal/gcc.ac
===================================================================
--- dtn-2.5.0.orig/oasys/aclocal/gcc.ac	2008-02-27 22:38:22.000000000 +0000
+++ dtn-2.5.0/oasys/aclocal/gcc.ac	2008-02-27 22:39:05.000000000 +0000
@@ -83,13 +83,13 @@
     dnl Figure out the version and set version-specific options
     dnl
     AC_CACHE_CHECK(for the version of the GNU C compiler, oasys_cv_prog_gccver, [
-      oasys_cv_prog_gccver=`$CC --version | head -1`
+      oasys_cv_prog_gccver=`$CC --version | head -n 1`
       oasys_cv_prog_gccver=`echo $oasys_cv_prog_gccver | sed 's/.*gcc.*(GCC) //'`
       oasys_cv_prog_gccver=`echo $oasys_cv_prog_gccver | sed 's/ .*//'`
     ])      
 
     AC_CACHE_CHECK(for the version of the GNU C++ compiler, oasys_cv_prog_gxxver, [
-      oasys_cv_prog_gxxver=`$CXX --version | head -1`
+      oasys_cv_prog_gxxver=`$CXX --version | head -n 1`
       oasys_cv_prog_gxxver=`echo $oasys_cv_prog_gxxver | sed 's/.*g++.*(GCC) //'`
       oasys_cv_prog_gxxver=`echo $oasys_cv_prog_gxxver | sed 's/ .*//'`
     ])