gnu: racket: Remove obsolete patch.

* gnu/packages/racket.scm (racket)[source](patches): Remove
"racket-store-checksum-override.patch", which is no longer needed since
we stopped injecting store paths into Racket files in commit 834aa48:
see <https://issues.guix.gnu.org/47180>.
* gnu/packages/patches/racket-store-checksum-override.patch: Delete file.
* gnu/local.mk (dist_patch_DATA): Remove it.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu/local.mk

@@ -1651,7 +1651,6 @@ dist_patch_DATA =						\
   %D%/packages/patches/rpcbind-CVE-2017-8779.patch		\
   %D%/packages/patches/rtags-separate-rct.patch			\
   %D%/packages/patches/racket-sh-via-rktio.patch		\
-  %D%/packages/patches/racket-store-checksum-override.patch	\
   %D%/packages/patches/remake-impure-dirs.patch			\
   %D%/packages/patches/retroarch-LIBRETRO_DIRECTORY.patch	\
   %D%/packages/patches/rnp-add-version.cmake.patch		\

gnu/packages/patches/racket-store-checksum-override.patch

@@ -1,42 +0,0 @@
-Racket uses checksums to test if it needs to recompile its source
-files to bytecode.  If Racket is updated by grafting, the source and
-bytecode files get updated, but the checksum stays the same.  Since
-the checksum no longer matches the source file, Racket tries to
-regenerate the bytecode and write it to the store, causing errors
-because the store is immutable.  This patch makes Racket ignore
-checksums for files in the store.
-
-See <https://debbugs.gnu.org/30680> for details.
-
----
---- a/collects/compiler/private/cm-minimal.rkt
-+++ b/collects/compiler/private/cm-minimal.rkt
-@@ -6,6 +6,7 @@
-          racket/list
-          racket/path
-          racket/promise
-+         racket/string
-          file/sha1
-          setup/cross-system
-          compiler/compilation-path
-@@ -268,7 +269,8 @@
-                (trace-printf "newer src... ~a > ~a" path-time path-zo-time)
-                (maybe-compile-zo deps path->mode roots path orig-path read-src-syntax up-to-date collection-cache new-seen
-                                  #:trying-sha1? sha1-only?)]
--              [(different-source-sha1-and-dep-recorded path deps)
-+              [(and (not (store-reference? path))
-+                    (different-source-sha1-and-dep-recorded path deps))
-                => (lambda (difference)
-                     (trace-printf "different src hash ~a for ~a..." difference path)
-                     (maybe-compile-zo deps path->mode roots path orig-path read-src-syntax up-to-date collection-cache new-seen
-@@ -1012,5 +1014,9 @@
-       #f
-       (list src-hash recorded-hash)))
-
-+(define (store-reference? path)
-+  (let ([store-prefix (or (getenv "NIX_STORE") "/gnu/store")])
-+    (string-prefix? (path->string path) store-prefix)))
-+
- ;; Make sure `recompile-from` is machine-independent so that
- ;; recompilation makes sense.
- ;; The compilation lock must is held for the source of `recompile-from`.

gnu/packages/racket.scm

@@ -63,11 +63,7 @@
                (base32
                 "047wpjblfzmf1msz7snrp2c2h0zxyzlmbsqr9bwsyvz3frcg0888"))
               (patches (search-patches
-                        "racket-sh-via-rktio.patch"
-                        ;; TODO: If we're no longer patching Racket source
-                        ;; files with store paths, we may also fix the
-                        ;; issue that necessitated the following patch:
-                        "racket-store-checksum-override.patch"))))
+                        "racket-sh-via-rktio.patch"))))
     (build-system gnu-build-system)
     (arguments
      `(#:configure-flags