-# 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 ${ac_top_builddir}. && pwd`
-ac_abs_srcdir=`cd "$ac_dir" && cd $ac_srcdir && pwd`
-ac_abs_top_srcdir=`cd "$ac_dir" && cd $ac_top_srcdir && pwd`
+
+# Do not use `cd foo && pwd` to compute absolute paths, because
+# the directories may not exist.
+case `pwd` in
+.) ac_abs_builddir="$ac_dir";;
+*)
+ case "$ac_dir" in
+ .) ac_abs_builddir=`pwd`;;
+ [\\/]* | ?:[\\/]* ) ac_abs_builddir="$ac_dir";;
+ *) ac_abs_builddir=`pwd`/"$ac_dir";;
+ esac;;
+esac
+case $ac_abs_builddir in
+.) ac_abs_top_builddir=${ac_top_builddir}.;;
+*)
+ case ${ac_top_builddir}. in
+ .) ac_abs_top_builddir=$ac_abs_builddir;;
+ [\\/]* | ?:[\\/]* ) ac_abs_top_builddir=${ac_top_builddir}.;;
+ *) ac_abs_top_builddir=$ac_abs_builddir/${ac_top_builddir}.;;
+ esac;;
+esac
+case $ac_abs_builddir in
+.) ac_abs_srcdir=$ac_srcdir;;
+*)
+ case $ac_srcdir in
+ .) ac_abs_srcdir=$ac_abs_builddir;;
+ [\\/]* | ?:[\\/]* ) ac_abs_srcdir=$ac_srcdir;;
+ *) ac_abs_srcdir=$ac_abs_builddir/$ac_srcdir;;
+ esac;;
+esac
+case $ac_abs_builddir in
+.) ac_abs_top_srcdir=$ac_top_srcdir;;
+*)
+ case $ac_top_srcdir in
+ .) ac_abs_top_srcdir=$ac_abs_builddir;;
+ [\\/]* | ?:[\\/]* ) ac_abs_top_srcdir=$ac_top_srcdir;;
+ *) ac_abs_top_srcdir=$ac_abs_builddir/$ac_top_srcdir;;
+ esac;;
+esac