Compatibility with GHC 8.10 and template-haskell 2.16.

Taken from 
https://raw.githubusercontent.com/archlinux/svntogit-community/packages/haskell-language-haskell-extract/trunk/ghc-8.10.patch

diff --git a/src/Language/Haskell/Extract.hs b/src/Language/Haskell/Extract.hs
index 3e8958b..43dfe04 100644
--- a/src/Language/Haskell/Extract.hs
+++ b/src/Language/Haskell/Extract.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 module Language.Haskell.Extract (
   functionExtractor,
   functionExtractorMap,
@@ -25,7 +26,11 @@ extractAllFunctions pattern =
 functionExtractor :: String -> ExpQ
 functionExtractor pattern =
   do functions <- extractAllFunctions pattern
-     let makePair n = TupE [ LitE $ StringL n , VarE $ mkName n]
+     let makePair n = TupE
+#if MIN_VERSION_template_haskell(2,16,0)
+                           $ map Just
+#endif
+                           [ LitE $ StringL n , VarE $ mkName n]
      return $ ListE $ map makePair functions
 
 
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<div class='path'>path: <a href='/guix/log/?id=2383da330da89774291f5b800ddc8d1980c9eae7'>root</a>/<a href='/guix/log/gnu?id=2383da330da89774291f5b800ddc8d1980c9eae7'>gnu</a>/<a href='/guix/log/gnu/tests.scm?id=2383da330da89774291f5b800ddc8d1980c9eae7'>tests.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/tests.scm?id=2383da330da89774291f5b800ddc8d1980c9eae7&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-11-05 23:23:23 +0100'>2023-11-05</span></td><td><a href='/guix/commit/gnu/tests.scm?id=0c695bbf8dbd5a5c1224f331a78b6316bc16e4d1'>tests: Honor system and target when lowering &lt;system-test&gt;.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/tests.scm (compile-system-test): Wrap ‘system-test-value’ call in
‘mparameterize’.

Change-Id: I4be28913a86f43059b0886ad2fcf81a9c699b730
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2023-04-21 16:16:38 +0200'>2023-04-21</span></td><td><a href='/guix/commit/gnu/tests.scm?id=a09c7da8f8d8e732f969cf0a09aaa78f87032ab1'>tests: Fork and exec a new Guile for the marionette REPL.</a><span class='msg-avail'>...<span class='msg-tooltip'>By merely forking PID 1, details from PID 1 (shepherd) would leak into
the marionette process, such as the set of modules in scope and state
inherited from the shepherd process (&lt;service&gt; instances, fibers,
etc.).  Running a fresh Guile instance avoids that.

* gnu/tests.scm (marionette-program): New procedure.
(marionette-shepherd-service): Change 'start' to use
'make-forkexec-constructor', and run the result of 'marionette-program'.
</span></span></td><td>Ludovic Courtès</td></tr>