gnu: GHC: Adjust tests for grep 3.8.

This fixes a test failure introduced in commit
c527b0ce23.

* gnu/packages/patches/ghc-testsuite-grep-compat.patch: New file.
* gnu/local.mk (dist_patch_DATA): Adjust accordingly.
* gnu/packages/haskell.scm (ghc-8.6, ghc-8.8, ghc-8.10)[native-inputs]: Patch
the 'ghc-testsuite' input.

gnu/local.mk

@@ -1160,6 +1160,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/ghc-4.patch				\
   %D%/packages/patches/ghc-8.0-fall-back-to-madv_dontneed.patch	\
   %D%/packages/patches/ghc-testsuite-dlopen-pie.patch		\
+  %D%/packages/patches/ghc-testsuite-grep-compat.patch		\
   %D%/packages/patches/ghc-language-haskell-extract-ghc-8.10.patch	\
   %D%/packages/patches/ghostscript-no-header-id.patch		\
   %D%/packages/patches/ghostscript-no-header-uuid.patch		\

gnu/packages/haskell.scm

@@ -763,7 +763,8 @@ (define-public ghc-8.6
            (uri (string-append
                  "https://www.haskell.org/ghc/dist/"
                  version "/" name "-" version "-testsuite.tar.xz"))
-           (patches (search-patches "ghc-testsuite-dlopen-pie.patch"))
+           (patches (search-patches "ghc-testsuite-dlopen-pie.patch"
+                                    "ghc-testsuite-grep-compat.patch"))
            (sha256
             (base32
              "0pw9r91g2np3i806g2f4f8z4jfdd7mx226cmdizk4swa7av1qf91"))
@@ -844,7 +845,8 @@ (define-public ghc-8.8
            (uri (string-append
                  "https://www.haskell.org/ghc/dist/"
                  version "/ghc-" version "-testsuite.tar.xz"))
-           (patches (search-patches "ghc-testsuite-dlopen-pie.patch"))
+           (patches (search-patches "ghc-testsuite-dlopen-pie.patch"
+                                    "ghc-testsuite-grep-compat.patch"))
            (sha256
             (base32
              "0c55pj2820q26rikhpf636sn4mjgqsxjrl94vsywrh79dxp3k14z"))
@@ -902,7 +904,8 @@ (define-public ghc-8.10
            (uri (string-append
                  "https://www.haskell.org/ghc/dist/"
                  version "/ghc-" version "-testsuite.tar.xz"))
-           (patches (search-patches "ghc-testsuite-dlopen-pie.patch"))
+           (patches (search-patches "ghc-testsuite-dlopen-pie.patch"
+                                    "ghc-testsuite-grep-compat.patch"))
            (sha256
             (base32
              "1zl25gg6bpx5601k8h3cqnns1xfc0nqgwnh8jvn2s65ra3f2g1nz"))

gnu/packages/patches/ghc-testsuite-grep-compat.patch

@@ -0,0 +1,39 @@
+Remove stray escapes to avoid warnings from grep 3.8 which breaks
+expected test output.
+
+diff --git a/testsuite/tests/hsc2hs/Makefile b/testsuite/tests/hsc2hs/Makefile
+--- a/testsuite/tests/hsc2hs/Makefile
++++ b/testsuite/tests/hsc2hs/Makefile
+@@ -47,5 +47,5 @@ T12504:
+ 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/$@.hs
+ endif
+diff --git a/testsuite/tests/numeric/should_run/T7014.primops b/testsuite/tests/numeric/should_run/T7014.primops
+--- a/testsuite/tests/numeric/should_run/T7014.primops
++++ b/testsuite/tests/numeric/should_run/T7014.primops
+@@ -1,8 +1,8 @@
+ and#
+ or#
+ uncheckedShift.*#
+-\+#
+-\-#
+++#
++-#
+ \*#
+ quotInt#
+ remInt#
+diff --git a/testsuite/tests/simplCore/should_compile/Makefile b/testsuite/tests/simplCore/should_compile/Makefile
+--- a/testsuite/tests/simplCore/should_compile/Makefile
++++ b/testsuite/tests/simplCore/should_compile/Makefile
+@@ -226,7 +226,7 @@ str-rules:
+ # g should have been collapsed into one defininition by CSE.
+ .PHONY: T13340
+ T13340:
+-	'$(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.