cpukit: Add signal mapping support

This adds a confdef option allowing an application to request mapping
machine exceptions to POSIX signals. This is required for some languages
such as Ada.

spec/build/cpukit/librtemscpu.yml

@@ -343,6 +343,7 @@ install:
   - cpukit/include/rtems/score/coresem.h
   - cpukit/include/rtems/score/coresemimpl.h
   - cpukit/include/rtems/score/cpustdatomic.h
+  - cpukit/include/rtems/score/exception.h
   - cpukit/include/rtems/score/freechain.h
   - cpukit/include/rtems/score/hash.h
   - cpukit/include/rtems/score/heap.h
@@ -497,6 +498,8 @@ links:
   uid: objdl
 - role: build-dependency
   uid: objdrvmgr
+- role: build-dependency
+  uid: objexceptionmapping
 - role: build-dependency
   uid: objgnat
 - role: build-dependency

spec/build/cpukit/objexceptionmapping.yml

@@ -0,0 +1,15 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+build-type: objects
+cflags: []
+copyrights:
+- Copyright (C) 2021 On-Line Applications Research (OAR)
+cppflags: []
+cxxflags: []
+enabled-by:
+- RTEMS_EXCEPTION_EXTENSIONS
+includes: []
+install: []
+links: []
+source:
+- cpukit/score/src/exceptionmapping.c
+type: build