OCaml + Termux

OCaml native on android!

NB since termux updated to binutils >= 2.29 only OCaml versions >= 4.06.0 will work (thx Kyle Stemen).

Easy way

Use pre-built OPAM for aarch64 to build OCaml

1. Install OPAM

   echo "deb [arch=all,aarch64] http://ygrek.org/files/debian/termux ./" >> "$PREFIX/usr/etc/apt/sources.list"
   apt-get update # repository is not signed for now :]
   apt install opam

2. Install OCaml

   apt install make clang
   opam init --comp=4.06.1+termux

True way

Build OCaml to build OPAM to build OCaml

NB termux lacks /bin/sh (and all other standard unix file paths for that matter), so the main problem during builds is hardcoded shell path in shebangs. To overcome it - remember to use sh ./script instead of ./script.

1. Remove opam and ocaml packages if present, remove ~/.opam to have clean state

2. Prepare proper build environment. NB termux comes with busybox, hence many utilities are present, but with limited features, need to install separate packages.

   apt install coreutils clang curl dash diffutils grep m4 make ncurses patch pkg-config

3. Build OCaml

   mkdir ~/tmp
   export TMPDIR="$HOME/tmp" # add to ~/.profile
   git clone https://github.com/ygrek/ocaml.git -b termux-4.06.1
   cd ocaml
   sh ./configure -prefix "$PREFIX"
   make world.opt install

4. Build OPAM

   curl -LO https://github.com/ocaml/opam/releases/download/1.2.2/opam-full-1.2.2.tar.gz
   tar -xzf opam-full-1.2.2.tar.gz
   cd opam-full-1.2.2/
   sed -i 's|/bin/sh|sh|' src/core/opamSystem.ml OCamlMakefile
   CONFIG_SHELL=sh sh ./configure -prefix "$PREFIX"
   OCAMLPARAM="safe-string=0,_" make lib-ext all install

5. Init OPAM (will use compiler built in step 3 as system switch)

   opam init

6. Install OCaml via OPAM and remove system OCaml (built in step 3) to avoid confusion with OPAM switches

   opam sw 4.06.1+termux
   rm "$PREFIX"/usr/man/man1/ocaml*
   rm "$PREFIX"/usr/bin/ocaml*
   rm -rf /data/data/com.termux/files/usr/lib/ocaml
   opam sw remove system

2018-06-25