Fix GHC 9.14 external Mach-O signed addends [skip ci]

Mach-O SIGNED_N embeds a -N addend for trailing instruction bytes.
Normalize that addend in the external relocation path before subtracting
the next-instruction address; keep internal section relocations unchanged.

Apply the RTS package patch only to the native Intel Darwin stage2
compiler. Source application and module scope/order/laziness checks pass;
the rebuilt compiler and the observed mobile SIGBUS still need CI.

scripts/nix/darwin-info-table-project.nix

@@ -13,6 +13,14 @@ lib.mkIf (
       # Stage1 must emit correct info tables for the stage2 boot libraries;
       # stage2 must retain that fix for application and interpreter objects.
       packages.ghc.patches = lib.mkAfter [ ./ghc914-macho-info-tables.patch ];
+
+      # Patch the native compiler's RTS without changing its configured
+      # source or stage1 bootstrap. External Mach-O SIGNED_N relocations
+      # carry a trailing-byte bias that must be normalized exactly once.
+      packages.rts.patches = lib.mkIf (
+        config.name == "ghc914-sh-stage2"
+        && config.compiler-nix-name == "ghc914-sh-stage1"
+      ) (lib.mkAfter [ ./ghc914-rts-macho-signed-addends.patch ]);
     })
   ];
 }

scripts/nix/ghc914-rts-macho-signed-addends.patch

@@ -0,0 +1,21 @@
+--- a/linker/MachO.c
++++ b/linker/MachO.c
+@@ -897,10 +897,18 @@
+ 
+             type = X86_64_RELOC_SIGNED;
+         }
+         else if (reloc->r_extern)
+         {
++            /* SIGNED_N's embedded addend already contains a -N bias for
++             * trailing instruction bytes. Normalize it before subtracting
++             * baseValue, which also includes N. Local relocations instead
++             * encode a displacement in the original image and are handled
++             * separately below.
++             */
++            thing += nextInstrAdj;
++
+             MachOSymbol *symbol = &symbols[reloc->r_symbolnum];
+             SymbolName* nm = symbol->name;
+             SymbolAddr* addr = NULL;
+ 
+             IF_DEBUG(linker_verbose, debugBelch("relocateSection: looking up external symbol %s\n", nm));