ocaml: phase 6 Sys module constants (+5 tests, 414 total)

os_type="SX", word_size=64, max_array_length, max_string_length,
executable_name="ocaml-on-sx", big_endian=false, unix=true,
win32=false, cygwin=false. Constants-only for now — argv/getenv_opt/
command would need host platform integration.

lib/ocaml/runtime.sx

@@ -366,6 +366,18 @@
      let printf fmt = print_string fmt
    end ;;
 
+   module Sys = struct
+     let os_type = \"SX\"
+     let word_size = 64
+     let max_array_length = 4611686018427387903
+     let max_string_length = 4611686018427387903
+     let executable_name = \"ocaml-on-sx\"
+     let big_endian = false
+     let unix = true
+     let win32 = false
+     let cygwin = false
+   end ;;
+
    module Hashtbl = struct
      let create n = _hashtbl_create n
      let add t k v = _hashtbl_add t k v

lib/ocaml/test.sh

@@ -1012,6 +1012,18 @@ cat > "$TMPFILE" << 'EPOCHS'
 (epoch 3102)
 (eval "(ocaml-type-of-program \"type t = A of bool | B of float;; A true\")")
 
+;; ── Sys module stubs ──────────────────────────────────────────
+(epoch 3200)
+(eval "(ocaml-run \"Sys.os_type\")")
+(epoch 3201)
+(eval "(ocaml-run \"Sys.word_size\")")
+(epoch 3202)
+(eval "(ocaml-run \"Sys.unix\")")
+(epoch 3203)
+(eval "(ocaml-run \"Sys.win32\")")
+(epoch 3204)
+(eval "(ocaml-run \"Sys.executable_name\")")
+
 EPOCHS
 
 OUTPUT=$(timeout 180 "$SX_SERVER" < "$TMPFILE" 2>/dev/null)
@@ -1601,6 +1613,13 @@ check 3100 "shape -> Int"                 '"shape -> Int"'
 check 3101 "TStr 'hi' : tag"              '"tag"'
 check 3102 "A true : t"                   '"t"'
 
+# ── Sys stubs ──────────────────────────────────────────────────
+check 3200 "Sys.os_type"                  '"SX"'
+check 3201 "Sys.word_size"                '64'
+check 3202 "Sys.unix"                     'true'
+check 3203 "Sys.win32"                    'false'
+check 3204 "Sys.executable_name"          '"ocaml-on-sx"'
+
 TOTAL=$((PASS + FAIL))
 if [ $FAIL -eq 0 ]; then
   echo "ok $PASS/$TOTAL OCaml-on-SX tests passed"