diff --git a/build/envsetup.sh b/build/envsetup.sh
index 5e6a761b92b3c01ccfbb264650058df9a77ec740..2556441de8e6895fec76f9c6d0d8ec963fb16894 100644
--- a/build/envsetup.sh
+++ b/build/envsetup.sh
@@ -20,12 +20,39 @@ function print_usage {
   echo " "
 }
 
+function gettop {
+  local TOPFILE=build/core/maple_variables.mk
+  if [ -n "$TOP" -a -f "$TOP/$TOPFILE" ] ; then
+    # The following circumlocution ensures we remove symlinks from TOP.
+    (cd $TOP; PWD= /bin/pwd)
+  else
+    if [ -f $TOPFILE ] ; then
+      # The following circumlocution (repeated below as well) ensures
+      # that we record the true directory name and not one that is
+      # faked up with symlink names.
+      #PWD= /bin/pwd
+      /bin/pwd -L
+    else
+      local HERE=$PWD
+      local T=
+      while [ \( ! \( -f $TOPFILE \) \) -a \( $PWD != "/" \) ]; do
+        \cd ..
+        T=`PWD= /bin/pwd -P`
+      done
+      \cd $HERE
+      if [ -f "$T/$TOPFILE" ]; then
+        echo $T
+      fi
+    fi
+  fi
+}
+
 if [ "$#" -lt 2 ]; then
   print_usage
 # return
 fi
 
-curdir=$(pwd)
+curdir=$(gettop)
 export MAPLE_ROOT=${curdir}
 export CASE_ROOT=${curdir}/testsuite
 export OUT_ROOT=${curdir}/output