stack-walker: Remove obsolete library

This code was only portable to 32-bit x86 (without frame pointer
elimination). Portable backtraces are now provided by the run-time via
libunwind.

* sources/lib/stack-walker/*: Remove.

* sources/registry/*/stack-walker: Remove

* sources/environment/dswank/library.dylan: Remove (commented-out)
  reference to the stack-walker library.

* OVERVIEW.txt: Remove mention of the stack-walker library.

* documentation/source/release-notes/2024.2.rst: Note removal of the
  stack-walker library.

OVERVIEW.txt

@@ -94,8 +94,6 @@ sources
     jam                 - Jam script interpreter.
     parser-run-time     - Support for parsers.
     source-records      - Reads source files and tracks location.
-    stack-walker        - Debugging on UNIX by walking the stack. Nowadays
-                          directly in the run-time.
     walker              - Build has-a tree.
   project-manager       - Takes care about dependencies of projects and actual
                           invocation of linker, etc.

documentation/source/release-notes/2024.2.rst

@@ -54,6 +54,11 @@ System
   :const:`$machine-architecture`.  The old name will remain, for backward
   compatibility.
 
+Other
+-----
+
+* The obsolete (32-bit x86-only) ``stack-walker`` library was removed.
+
 Contributors
 ============
 

sources/environment/dswank/library.dylan

@@ -19,7 +19,6 @@ define library dswank
   use file-source-records;
   use system;
   use registry-projects;
-  //use stack-walker;
   use release-info;
   use dfmc-back-end-implementations;
 end library;
@@ -46,7 +45,6 @@ define module dswank
   use file-system;
   use locators;
   use registry-projects;
-  //use stack-walker;
   use release-info;
   use operating-system;
 end module;