Import xapi-backtrace into XAPI (#6957)

To make changes to the backtrace library we need to first import it into
XAPI.
Used `git subtree` to import it with its full history.

Follow-up pull-requests will update it to:
* use new functions from Printexc (introduced in 4.02 and 4.11) that
avoids parsing the strings
* deduplicate entries
* print function names and characters, not just line numbers

Eventually it could also be updated to capture a backtrace automatically
(e.g. a `Backtrace.try_with` function).

A chainbuild passed using this PR, together with another internal PR
that drops references to the external `xapi-backtrace` module from other
internal packages.

Author: edwintorok

dune-project

@@ -235,7 +235,6 @@
   fmt
   logs
   mtime
-  xapi-backtrace
   (xapi-stdext-pervasives (= :version))))
 
 (package
@@ -322,7 +321,6 @@
   uuidm
   uutf
   x509
-  xapi-backtrace
   xapi-log
   xapi-types
   xapi-stdext-pervasives
@@ -451,7 +449,6 @@
   uutf
   uuidm
   x509
-  xapi-backtrace
   (xapi-client
    (= :version))
   (xapi-cli-protocol
@@ -764,7 +761,6 @@
   uri
   (uuid
    (= :version))
-  xapi-backtrace
   (xapi-idl
    (= :version))
   (xapi-log
@@ -795,7 +791,6 @@
   rpclib
   (uuid
    (= :version))
-  xapi-backtrace
   (xapi-log
    (= :version))
   (xapi-stdext-pervasives
@@ -842,7 +837,7 @@
    (>= 4.08))
   logs
   (odoc :with-doc)
-  xapi-backtrace))
+  ))
 
 (package
  (name xapi-stdext-std)
@@ -902,7 +897,6 @@
     (>= 0.21.2)
     :with-test))
   (odoc :with-doc)
-  xapi-backtrace
   unix-errno
   (xapi-stdext-pervasives
    (= :version))

ocaml/database/dune

@@ -53,7 +53,7 @@
   httpsvr
   unix
   uuid
-  xapi-backtrace
+  backtrace
   xapi-datamodel
   xapi-log
   (re_export xapi-schema)

ocaml/forkexecd/lib/dune

@@ -12,7 +12,7 @@
    rpclib.xml
    unix
    uuid
-   xapi-backtrace
+   backtrace
    xapi-log
    xapi-stdext-pervasives
    xapi-stdext-unix

ocaml/gencert/dune

@@ -18,7 +18,7 @@
     rresult
     unix
     x509
-    xapi-backtrace
+    backtrace
     xapi-consts
     xapi-log
     xapi-inventory

ocaml/idl/dune

@@ -13,7 +13,7 @@
     sexplib0
     sexpr
     threads
-    xapi-backtrace
+    backtrace
     xapi-consts
     xapi-schema
     clock

ocaml/libs/backtrace/.git-blame-ignore-revs

@@ -0,0 +1,3 @@
+_build
+*.install
+.merlin

ocaml/libs/backtrace/.gitignore

@@ -0,0 +1,26 @@
+## v0.8 (13-Mar-2026)
+* Set a license
+* Provide a new with_backtraces that prevents printing invalid traces
+* Fix losing backtraces when reraising
+* Add regression tests
+
+## v0.7 (18-Sep-2018)
+* Remove dependency on full sexplib
+* Simplify jbuild, quiet warnings, move to dune and update opam dependencies
+* jbuild: remove ppx_deriving_rpc from libraries
+* Move to dune and update opam dependencies
+
+## v0.6 (16-May-2018)
+* Add support for ppx_sexp_conv >= v0.11.0
+
+## v0.5 (04-Aug-2017)
+* port to jbuilder
+
+## v0.3 (21-Aug-2015)
+* correct ordering
+* add rpc to opam
+* add doc gen to _oasis
+
+## v0.2 (20-Nov-2014)
+* store backtraces as lists of records rather than strings
+* change the API for "importing" backtraces from other languages