gnu: ghc-9.2: Adapt testsuite to grep 3.8.

Starting with version 3.8, grep emits warning messages when pattern
contain spurious slashes:

    grep '\+' /dev/null
    grep: warning: stray \ before +

GHC’s testsuite does not expect that and fails.

* gnu/packages/patches/ghc-9.2-grep-warnings.patch: New file.
* gnu/local.mk: Add it.
* gnu/packages/haskell.scm (ghc-9.2)[native-inputs]: Add patch.

gnu/local.mk

@@ -1193,6 +1193,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/gettext-libunicode-update.patch		\
   %D%/packages/patches/ghc-8.0-fall-back-to-madv_dontneed.patch	\
   %D%/packages/patches/ghc-9.2-glibc-2.33-link-order.patch \
+  %D%/packages/patches/ghc-9.2-grep-warnings.patch \
   %D%/packages/patches/ghc-testsuite-dlopen-pie.patch		\
   %D%/packages/patches/ghc-testsuite-grep-compat.patch		\
   %D%/packages/patches/ghc-bloomfilter-ghc9.2.patch	\

gnu/packages/haskell.scm

@@ -1354,7 +1354,8 @@ interactive environment for the functional language Haskell.")
                     version "/ghc-" version "-testsuite.tar.xz"))
              (sha256
               (base32
-               "19ha0hidrijawy53vm2r0sgml5zkl8126mqy7p0pyacmw3k7913l"))))
+               "19ha0hidrijawy53vm2r0sgml5zkl8126mqy7p0pyacmw3k7913l"))
+             (patches (search-patches "ghc-9.2-grep-warnings.patch"))))
          ,@(filter (match-lambda
                      (("ghc-bootstrap" . _) #f)
                      (("ghc-testsuite" . _) #f)

gnu/packages/patches/ghc-9.2-grep-warnings.patch

@@ -0,0 +1,37 @@
+--- ghc-9.2.5/testsuite/tests/numeric/should_run/T7014.primops.orig	2023-03-12 14:42:11.338540492 +0100
++++ ghc-9.2.5/testsuite/tests/numeric/should_run/T7014.primops	2023-03-12 14:42:13.735608896 +0100
+@@ -1,9 +1,9 @@
+ and#
+ or#
+ uncheckedShift.*#
+++#
++-#
++*#
+-\+#
+-\-#
+-\*#
+ quotInt#
+ remInt#
+ plusFloat#
+--- ghc-9.2.5/testsuite/tests/hsc2hs/Makefile.orig	2023-03-12 14:40:03.825939306 +0100
++++ ghc-9.2.5/testsuite/tests/hsc2hs/Makefile	2023-03-12 14:40:07.961054835 +0100
+@@ -54,7 +54,7 @@
+ ifeq "$(WINDOWS)" "YES"
+ 	grep '{-# LINE 1 \"T12504\\\\path\\\\to\\\\$@\.hsc\" #-}' T12504/path/to/$@.hs
+ else
++	grep '{-# LINE 1 "T12504/path/to/$@\.hsc" #-}' T12504/path/to/$@.hs
+-	grep '{-# LINE 1 \"T12504/path/to/$@\.hsc\" #-}' T12504/path/to/$@.hs
+ endif
+ 
+ .PHONY: T15758
+--- ghc-9.2.5/testsuite/tests/simplCore/should_compile/Makefile.orig	2023-03-12 14:41:16.204974035 +0100
++++ ghc-9.2.5/testsuite/tests/simplCore/should_compile/Makefile	2023-03-12 14:41:17.832020067 +0100
+@@ -253,7 +253,7 @@
+ # g should have been collapsed into one defininition by CSE.
+ .PHONY: T13340
+ T13340:
++	'$(TEST_HC)' $(TEST_HC_OPTS) -c -O T13340.hs -ddump-simpl -dsuppress-all | grep -c '+#'
+-	'$(TEST_HC)' $(TEST_HC_OPTS) -c -O T13340.hs -ddump-simpl -dsuppress-all | grep -c '\+#'
+ 
+ 
+ # We expect to see all dictionaries specialized away.