diff --git a/configure b/configure
index ad7834d94..bc5fb2247 100755
--- a/configure
+++ b/configure
@@ -12,12 +12,11 @@ use Pod::Usage;
 
 # We do not check for the following programs; we assume they are standard:
 # - binutils, gcc, as, ld, the GNU toolchain
-# - make, sh?, perl?
+# - make, perl, bash
 # - diffutils, fileutils, findutils, grep, patchutils, sh-utils
-# - diff?, patch?
-# 
+
 # - TODO findutils ?? need good gnu find, not macos find
-#   which adds some extra '//' in paths which bother pfff
+#   which adds some extra '//' in paths which bothers pfff
 # - STILL? sharutils, for obrowser/ocsigen  use of uuencode
 
 # If want to run the tests need also:
@@ -37,15 +36,16 @@ my $prefix="/usr/local";
 
 my $bt=0;
 
-my $graphics=0; # X11 graphics.cma
 my $visual=1; # cairo, codemap
+my $graphics=0; # X11 graphics.cma
 my $gui=1; # gtk, pfff_browser
 
+my $opt= ""; # ocamlc.opt ?
+my $ocamlc_flags = ""; #ocamlc -?
+my $ocaml_version = 3112;
 
 my $facebook=0; 
 
-#my $opt=".opt"; # also set in env.sh
-
 my $man = 0;
 my $help = 0;
 
@@ -58,9 +58,9 @@ GetOptions (
 
     "bt!" => \$bt,
 
+    "visual!" => \$visual,
     "gui!" => \$gui,
     "graphics!" => \$graphics,
-    "visual!" => \$visual,
 
     "with-all" => sub { 
         $facebook = 0;
@@ -177,18 +177,23 @@ my $arch = `uname`;
 # We need 4.01 for changes in the .cmt format
 $error += 
     check_config("echo \"1;;\\n\" | ocaml |",
-                 "(Objective|OCaml)(.*) (4\.01\.*)",
+                 "(Objective|OCaml)(.*) ([34]\.*.*)",
                  "OCaml (the wonderful language) is present.",
                  "The program ocaml is missing or is not a good version. We need at least 4.01",
                  );
 show_error_msg_and_exit_if_error($error);
 
-#not really used for now:
-#$error2 += check_config("glimpse 2>&1 |",
-#		       "This is glimpse version",
-#		       "glimpse is present.",
-#		       "The program glimpse is missing.",
-#		      );
+my $command = "echo \"1;;\\n\" | ocaml |";
+my $full = cat($command);
+my $res = join(" ", @{$full});
+if ($res =~ /(Objective|OCaml)(.*) ([34])\.([0-9]+).([0-9]+)/) {
+    my $major = $3;
+    my $minor = $4;
+    my $other = $5;
+    $ocaml_version = $major * 1000 + $minor * 10 + $other;
+} else {
+    die "wrong version of ocaml";
+}
 
 #---------------------------------------------------------------
 # Developers tools
@@ -219,6 +224,17 @@ show_error_msg_and_exit_if_error($error);
 # More developers tools
 #---------------------------------------------------------------------
 
+# The OPTBIN variable is here to allow to use ocamlc.opt instead of
+# ocaml, when it is available, which speeds up compilation. So
+# if you want the fast version of the ocaml chain tools, set this var
+# or setenv it to \".opt\" in your startup script.
+# todo: detect if possible?
+$opt = ".opt";
+
+# -bin-annot is for codegraph, it needs ocaml 4.00,
+# -absname is for tuareg mode under my mac, it also needs ocaml 4.00
+$ocamlc_flags="-bin-annot -absname";
+
 #---------------------------------------------------------------------
 # Librairies
 #---------------------------------------------------------------------
@@ -292,7 +308,7 @@ see install.txt or type ./configure --help
 
 pr2 "$project target prefix: $prefix (you can use --prefix to override it)";
 pr2 "Generating Makefile.config (BT=$bt, GUI=$gui, VISUAL=$visual)";
-pr2 " (see also --help)";
+pr2 " (see also configure --help)";
 open(CONFIG, ">Makefile.config");
 print CONFIG "# autogenerated by configure
 
@@ -324,34 +340,24 @@ FEATURE_GRAPHICS=$graphics
 FEATURE_VISUAL=$visual
 
 FEATURE_FACEBOOK=$facebook
-";
 
+OPTBIN=$opt
+OCAMLCFLAGS_EXTRA=$ocamlc_flags
+OCAMLVERSION=$ocaml_version
+";
 
-# The OPTBIN variable is here to allow to use ocamlc.opt instead of
-# ocaml, when it is available, which speeds up compilation. So
-# if you want the fast version of the ocaml chain tools, set this var
-# or setenv it to \".opt\" in your startup script.
-#OPTBIN=$opt
 
 pr2 "Generating commons/features.ml";
 `cpp -DFEATURE_GUI=$gui -DFEATURE_BACKTRACE=$bt commons/features.ml.in > commons/features.ml`;
 
-#pr2 "Generating appropriate links in yyy/ (python=$python)";
-
 pr2 "Generating globals/config_pfff.ml";
-#old: my $command = "perl -p -i -e 's#Not_found.\*#Not_found->\\\"$src\\\"#' globals/config.ml";
-my $command = "perl -p -e 's#Not_found1.\*#Not_found->\\\"$src\\\"#' globals/config_pfff.ml.in > globals/config_pfff.ml";
-`$command`;
-
+`perl -p -e 's#Not_found1.\*#Not_found->\\\"$src\\\"#' globals/config_pfff.ml.in > globals/config_pfff.ml`;
 if($facebook) {
     my ($server) = `cat facebook/pfff_logger.config`;
     `perl -p -i -e 's#Not_found2.\*#Not_found-> Some \\\"$server\\\"#' globals/config_pfff.ml`;
 }
-
 `perl -p -i -e 's#Not_found[0-9]#Not_found#' globals/config_pfff.ml`;
 
-#`touch test.ml`;
-
 if($error || $error2) { 
     pr2 "!!Problems during ./configure!!";
 }
diff --git a/env.sh b/env.sh
index e4e72a9c6..c9ef67538 100644
--- a/env.sh
+++ b/env.sh
@@ -6,22 +6,14 @@ Are you sure you ran this script from the source directory of pfff?
 fi
 
 # To compile the source, using pad installation.
-#echo setting OPAM
-#eval `~pad/packages/Linux/bin/opam config env`
+echo setting OPAM
+#eval `~pad/packages/Linux/bin/opam config env` does not work, it expands
+# to /home/pieter/.opam/... when done by another user => inlined here
 export CAML_LD_LIBRARY_PATH=/home/pad/.opam/4.01.0/lib/stublibs
 export OCAML_TOPLEVEL_PATH=/home/pad/.opam/4.01.0/lib/toplevel
 export MANPATH=/home/pad/.opam/4.01.0/man:
 export PATH=/home/pad/.opam/4.01.0/bin:/home/pad/packages/sbin:/home/pad/packages/bin:/home/pad/bin:/usr/kerberos/bin:/opt/local/bin:/usr/local/bin:/bin:/usr/bin:/usr/facebook/ops/scripts:/usr/facebook/scripts:/usr/facebook/scripts:/usr/facebook/scripts/db:/usr/local/sbin:/usr/sbin:/sbin:/mnt/vol/engshare/svnroot/tfb/trunk/www/scripts/bin:/mnt/vol/engshare/admin/scripts/hg:/mnt/vol/engshare/admin/scripts/git:/mnt/vol/engshare/admin/scripts:/home/pad/www/scripts/bin:/home/pad/packages/Linux/bin
 
-
-# for faster compiler
-echo setting OPTBIN
-export OPTBIN=.opt
-
-# -bin-annot is for codegraph, it needs ocaml 4.00,
-# -absname is for tuareg mode under my mac, it also needs ocaml 4.00
-export OCAMLCFLAGS_EXTRA="-bin-annot -absname"
-
 # for exception stack traces
 echo setting OCAMLRUNPARAM
 export OCAMLRUNPARAM="b"
@@ -30,3 +22,7 @@ export OCAMLRUNPARAM="b"
 # to find the tests/ files.
 echo setting PFFF_HOME
 export PFFF_HOME=`pwd`
+
+# for ocamlgtk
+echo setting PKG_CONFIG_PATH
+export PKG_CONFIG_PATH=/usr/X11/lib/pkgconfig
\ No newline at end of file
diff --git a/lang_ml/analyze/Makefile b/lang_ml/analyze/Makefile
index ccfa196d3..0667847d8 100644
--- a/lang_ml/analyze/Makefile
+++ b/lang_ml/analyze/Makefile
@@ -91,19 +91,19 @@ clean::
 	rm -f $(TARGET).top
 
 
-CPP=-pp 'cpp -DOCAML_VERSION=4000'
+PP=-pp "cpp -DOCAML_VERSION=$(OCAMLVERSION)"
 
 meta_ast_cmt.cmo: meta_ast_cmt.ml
-	$(OCAMLC) $(CPP)  -c $<
+	$(OCAMLC) $(PP)  -c $<
 
 meta_ast_cmt.cmx: meta_ast_cmt.ml
-	$(OCAMLOPT) $(CPP) -c $<
+	$(OCAMLOPT) $(PP) -c $<
 
 graph_code_cmt.cmo: graph_code_cmt.ml
-	$(OCAMLC) $(CPP)  -c $<
+	$(OCAMLC) $(PP)  -c $<
 
 graph_code_cmt.cmx: graph_code_cmt.ml
-	$(OCAMLOPT) $(CPP) $<
+	$(OCAMLOPT) $(PP) $<
 
 ##############################################################################
 # Literate Programming rules