Updated unison to v2.51.2 (#16772)

The current package does not work. Also several ocaml versions do
not compile such as 4.09.0. Updated to the new ocaml version to
4.10.0, which is now a prerequisite.

var/spack/repos/builtin/packages/ocaml/package.py

@@ -29,12 +29,22 @@ class Ocaml(Package):
 
     sanity_check_file = ['bin/ocaml']
 
+    variant(
+        'force-safe-string', default=True,
+        description='Enforce safe (immutable) strings'
+    )
+
     def url_for_version(self, version):
         url = "http://caml.inria.fr/pub/distrib/ocaml-{0}/ocaml-{1}.tar.gz"
         return url.format(str(version)[:-2], version)
 
     def install(self, spec, prefix):
-        configure('-prefix', '{0}'.format(prefix))
+        base_args = ['-prefix', '{0}'.format(prefix)]
+
+        if self.spec.satisfies('~force-safe-string'):
+            base_args += ['--disable-force-safe-string']
+
+        configure(*(base_args))
 
         make('world.opt')
         make('install', 'PREFIX={0}'.format(prefix))

var/spack/repos/builtin/packages/unison/4.08-compatibility.patch

+From 29fa058c3127f3b47c347dcaa4a94f4c0e888308 Mon Sep 17 00:00:00 2001
+From: Jaap Boender <jaapb@kerguelen.org>
+Date: Thu, 21 Mar 2019 12:26:51 +0000
+Subject: [PATCH] Compatibility with OCaml 4.08
+
+---
+ src/files.ml                 | 2 +-
+ src/recon.ml                 | 4 ++--
+ src/system/system_generic.ml | 2 +-
+ 3 files changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/src/files.ml b/src/files.ml
+index ba42ad57..5babf21e 100644
+--- a/src/files.ml
++++ b/src/files.ml
+@@ -722,7 +722,7 @@ let get_files_in_directory dir =
+   with End_of_file ->
+     dirh.System.closedir ()
+   end;
+-  Sort.list (<) !files
++  List.sort String.compare !files
+ 
+ let ls dir pattern =
+   Util.convertUnixErrorsToTransient
+diff --git a/src/recon.ml b/src/recon.ml
+index 5ed358d7..0df2cfe4 100644
+--- a/src/recon.ml
++++ b/src/recon.ml
+@@ -651,8 +651,8 @@ let rec reconcile
+ 
+ (* Sorts the paths so that they will be displayed in order                   *)
+ let sortPaths pathUpdatesList =
+-  Sort.list
+-    (fun (p1, _) (p2, _) -> Path.compare p1 p2 <= 0)
++  List.sort
++    Path.compare
+     pathUpdatesList
+ 
+ let rec enterPath p1 p2 t =
+diff --git a/src/system/system_generic.ml b/src/system/system_generic.ml
+index ed8e18f3..0e28a781 100755
+--- a/src/system/system_generic.ml
++++ b/src/system/system_generic.ml
+@@ -47,7 +47,7 @@ let open_out_gen = open_out_gen
+ let chmod = Unix.chmod
+ let chown = Unix.chown
+ let utimes = Unix.utimes
+-let link = Unix.link
++let link s d = Unix.link s d
+ let openfile = Unix.openfile
+ let opendir f =
+   let h = Unix.opendir f in

var/spack/repos/builtin/packages/unison/large.patch

+diff -Nrua /usr/ports/net/unison/patches/patch-bytearray_stubs_c ./patches/patch-bytearray_stubs_c
+--- /usr/ports/net/unison/patches/patch-bytearray_stubs_c	Thu Jan  1 01:00:00 1970
++++ ./patches/patch-bytearray_stubs_c	Tue Jan 17 08:44:39 2017
+@@ -0,0 +1,45 @@
++Fix rare SIGSEGV when transferring large replicas.
++Fix a theoretical integer overflow. 
++
++Patches from here:
++https://caml.inria.fr/mantis/view.php?id=7431#c17026
++and here:
++https://caml.inria.fr/mantis/view.php?id=7431#c16962
++
++Related issue reports:
++https://github.com/bcpierce00/unison/issues/48
++https://caml.inria.fr/mantis/view.php?id=7431
++https://bugzilla.redhat.com/show_bug.cgi?id=1401759
++
++Thanks to Alex Markley and OCaml developers
++--- bytearray_stubs.c.orig	Tue Jan 17 08:41:00 2017
+++++ bytearray_stubs.c	Tue Jan 17 08:41:21 2017
++@@ -5,6 +5,7 @@
++ 
++ #include "caml/intext.h"
++ #include "caml/bigarray.h"
+++#include "caml/memory.h"
++ 
++ CAMLprim value ml_marshal_to_bigarray(value v, value flags)
++ {
++@@ -21,15 +22,18 @@ CAMLprim value ml_marshal_to_bigarray(value v, value f
++ 
++ CAMLprim value ml_unmarshal_from_bigarray(value b, value ofs)
++ {
+++  CAMLparam1(b); /* Holds [b] live until unmarshalling completes. */
+++  value result;
++   struct caml_bigarray *b_arr = Bigarray_val(b);
++-  return input_value_from_block (Array_data (b_arr, ofs),
+++  result = input_value_from_block (Array_data (b_arr, ofs),
++                                  b_arr->dim[0] - Long_val(ofs));
+++  CAMLreturn(result);
++ }
++ 
++ CAMLprim value ml_blit_string_to_bigarray
++ (value s, value i, value a, value j, value l)
++ {
++-  char *src = String_val(s) + Int_val(i);
+++  char *src = String_val(s) + Long_val(i);
++   char *dest = Array_data(Bigarray_val(a), j);
++   memcpy(dest, src, Long_val(l));
++   return Val_unit;

var/spack/repos/builtin/packages/unison/package.py

@@ -15,18 +15,22 @@ class Unison(Package):
        other."""
 
     homepage = "https://www.cis.upenn.edu/~bcpierce/unison/"
-    url      = "https://www.seas.upenn.edu/~bcpierce/unison//download/releases/stable/unison-2.48.4.tar.gz"
+    url      = "https://github.com/bcpierce00/unison/archive/v2.51.2.tar.gz"
+    maintainers = ["hseara"]
 
-    version('2.48.4', sha256='30aa53cd671d673580104f04be3cf81ac1e20a2e8baaf7274498739d59e99de8')
+    version('2.51.2', sha256='a2efcbeab651be6df69cc9b253011a07955ecb91fb407a219719451197849d5e')
+    version('2.48.15v4', sha256='f8c7e982634bbe1ed6510fe5b36b6c5c55c06caefddafdd9edc08812305fdeec')
 
-    depends_on('ocaml', type='build')
+    depends_on('ocaml@4.10.0:~force-safe-string', type='build')
+
+    patch('large.patch', level=0)
+    patch('4.08-compatibility.patch', when='^ocaml@4.08:')
 
     parallel = False
 
     def install(self, spec, prefix):
-        make('./mkProjectInfo')
-        make('UISTYLE=text')
+        make('UISTYLE=text DEBUGGING=false THREADS=true')
 
         mkdirp(prefix.bin)
-        install('unison', prefix.bin)
+        install('src/unison', prefix.bin)
         set_executable(join_path(prefix.bin, 'unison'))