[Caml-list] Errors in installing 'lwt'

[Helmut Brandl <helmut.brandl@gmx.net>]

Hello,

I am trying to install 'js_of_ocaml' with 'opam' and run into some 
problems. It seems that the ocaml compile cannot compile the 'lwt' package.

$opam list
Installed packages for system:
base-unix           base  Unix library distributed with the OCaml compiler
camlp4     4.02.0+system  Camlp4 is a system for writing extensible 
parsers for programming languages
cmdliner           0.9.5  Declarative definition of command line 
interfaces for OCaml
menhir          20140422  LR(1) parser generator
ocamlfind          1.5.3  A library manager for OCaml
ppx_tools         0.99.1  Tools for authors of ppx rewriters and other 
syntactic tools

opam install js_of_ocaml
The following actions will be performed:
  - install lwt.2.4.6 [required by js_of_ocaml]
  - install js_of_ocaml.2.5
2 to install | 0 to reinstall | 0 to upgrade | 0 to downgrade | 0 to remove
Do you want to continue ? [Y/n]

=-=-= Installing lwt.2.4.6 =-=-=
Building lwt.2.4.6:
   ./configure --prefix /home/helmut/.opam/system --disable-libev 
--disable-react --disable-ssl --enable-unix --enable-extra 
--disable-preemptive --disable-glib --enable-ppx
   make build
   make install
[ERROR] The compilation of lwt.2.4.6 failed.
Removing lwt.2.4.6.
   ocamlfind remove lwt

[ERROR] Due to some errors while processing lwt.2.4.6, the following 
actions will NOT proceed:
  - install js_of_ocaml.2.5

===== ERROR while installing lwt.2.4.6 =====
# opam-version 1.1.1
# os           linux
# command      ./configure --prefix /home/helmut/.opam/system 
--disable-libev --disable-react --disable-ssl --enable-unix 
--enable-extra --disable-preemptive --disable-glib --enable-ppx
# path         /home/helmut/.opam/system/build/lwt.2.4.6
# compiler     system (4.02.0)
# exit-code    1
# env-file /home/helmut/.opam/system/build/lwt.2.4.6/lwt-25223-ffb3fd.env
# stdout-file /home/helmut/.opam/system/build/lwt.2.4.6/lwt-25223-ffb3fd.out
# stderr-file /home/helmut/.opam/system/build/lwt.2.4.6/lwt-25223-ffb3fd.err
### stderr ###
# ...[truncated]
# W: Failure("Command ''/home/helmut/.opam/system/bin/ocamlfind' query 
-format %d camlp4 > '/tmp/oasis-c39eab.txt'' terminated with error code 2")
# ocamlfind: Package `camlp4' not found
# W: Failure("Command ''/home/helmut/.opam/system/bin/ocamlfind' query 
-format %d camlp4 > '/tmp/oasis-5e24a6.txt'' terminated with error code 2")
# ocamlfind: Package `camlp4.quotations.o' not found
# W: Failure("Command ''/home/helmut/.opam/system/bin/ocamlfind' query 
-format %d camlp4.quotations.o > '/tmp/oasis-f94904.txt'' terminated 
with error code 2")
# E: Cannot find buildable internal library 'lwt-preemptive' when 
checking build depends
# E: Cannot find findlib package camlp4
# E: Cannot find findlib package camlp4.extend
# E: Cannot find findlib package camlp4.quotations.o
# E: Failure("4 configuration errors")

'opam install js_of_ocaml' failed.


Can anybody help (or if this list is not the right location to ask can 
you redirect me)?

Thanks in advance
Helmut