diff --git a/configure b/configure
index f5bbc77..3f4ed4d 100755
--- a/configure
+++ b/configure
@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.in Revision: 1.420 .
+# From configure.in Revision: 1.421 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.53 for python 2.3.
 #
@@ -908,7 +908,7 @@
 # Don't blindly perform a `cd "$ac_dir"/$ac_foo && pwd` since $ac_foo can be
 # absolute.
 ac_abs_builddir=`cd "$ac_dir" && cd $ac_builddir && pwd`
-ac_abs_top_builddir=`cd "$ac_dir" && cd $ac_top_builddir && pwd`
+ac_abs_top_builddir=`cd "$ac_dir" && cd ${ac_top_builddir}. && pwd`
 ac_abs_srcdir=`cd "$ac_dir" && cd $ac_srcdir && pwd`
 ac_abs_top_srcdir=`cd "$ac_dir" && cd $ac_top_srcdir && pwd`
 
@@ -13123,6 +13123,7 @@
 fi
 rm -f conftest.$ac_objext conftest.$ac_ext
 
+# On some systems, setgroups is in unistd.h, on others, in grp.h
 echo "$as_me:$LINENO: checking for setgroups" >&5
 echo $ECHO_N "checking for setgroups... $ECHO_C" >&6
 cat >conftest.$ac_ext <<_ACEOF
@@ -13131,6 +13132,9 @@
 
 #include "confdefs.h"
 #include <unistd.h>
+#ifdef HAVE_GRP_H
+#include <grp.h>
+#endif
 
 #ifdef F77_DUMMY_MAIN
 #  ifdef __cplusplus
@@ -18450,7 +18454,7 @@
 # Don't blindly perform a `cd "$ac_dir"/$ac_foo && pwd` since $ac_foo can be
 # absolute.
 ac_abs_builddir=`cd "$ac_dir" && cd $ac_builddir && pwd`
-ac_abs_top_builddir=`cd "$ac_dir" && cd $ac_top_builddir && pwd`
+ac_abs_top_builddir=`cd "$ac_dir" && cd ${ac_top_builddir}. && pwd`
 ac_abs_srcdir=`cd "$ac_dir" && cd $ac_srcdir && pwd`
 ac_abs_top_srcdir=`cd "$ac_dir" && cd $ac_top_srcdir && pwd`