Add windows R_X86_64_PC64 relocation support

Author: angerman

overlays/bootstrap.nix

@@ -183,6 +183,9 @@ in {
                 ++ fromUntil "8.6.5"  "9.5"    ./patches/ghc/ghc-hpc-response-files.patch   # https://gitlab.haskell.org/ghc/ghc/-/merge_requests/8194
                 ++ final.lib.optionals (final.stdenv.targetPlatform.isWindows) (fromUntil "9.4.1"  "9.4.5"  ./patches/ghc/ghc-9.4-hadrian-win-cross.patch)
                 ++ final.lib.optionals (final.stdenv.targetPlatform.isWindows) (fromUntil "9.8.1"  "9.10"   ./patches/ghc/ghc-9.8-hadrian-win-cross.patch)
+                # support R_X86_64_PC64 (ELF constant 24) - IMAGE_REL_AMD64_SREL32 (PE constant 14), which seems to appear with 9.6 more frequently, and
+                # results in "unhandled PEi386 relocation type 14".
+                ++ final.lib.optionals (final.stdenv.targetPlatform.isWindows) (fromUntil "9.4.1"  "9.10"   ./patches/ghc/win-reloc-x86_64-pc64.patch)
                 ++ fromUntil "9.4.5"  "9.4.6"  ./patches/ghc/ghc-9.4.5-include-order-fix.patch
                 ++ fromUntil "9.6.2"  "9.8"    ./patches/ghc/ghc-9.4.5-include-order-fix.patch
                 ++ fromUntil "9.6.1"  "9.10"   ./patches/ghc/MR10116.patch

overlays/patches/ghc/win-reloc-x86_64-pc64.patch

@@ -0,0 +1,20 @@
+diff --git a/rts/linker/PEi386.c b/rts/linker/PEi386.c
+index 0b328df..c404992 100644
+--- a/rts/linker/PEi386.c
++++ b/rts/linker/PEi386.c
+@@ -2071,6 +2071,15 @@ ocResolve_PEi386 ( ObjectCode* oc )
+                    *(uint32_t *)pP = (uint32_t)v;
+                    break;
+                }
++            case 14: /* R_X86_64_PC64 (ELF constant 24) - IMAGE_REL_AMD64_SREL32 (PE constant 14) */
++               {
++                   /* mingw will emit this for a pc-rel 64 relocation */
++                   uint64_t A;
++                   checkProddableBlock(oc, pP, 8);
++                   A = *(uint64_t*)pP;
++                   *(uint64_t *)pP = S + A - (intptr_t)pP;
++                   break;
++               }
+             case 4: /* R_X86_64_PC32 (ELF constant 2) - IMAGE_REL_AMD64_REL32 (PE constant 4) */
+                {
+                    intptr_t v;