configure: Always create the VERSION file

Teach the `configure` script to create the `VERSION` file.
This will serve as the stable interface to allow the user to determine
the version number of a working tree.

Fixes #22322.

configure.ac

@@ -1214,6 +1214,9 @@ AC_CONFIG_FILES(
   distrib/configure.ac
 ])
 
+dnl Create the VERSION file, satisfying #22322.
+printf "$ProjectVersion" > VERSION
+
 AC_OUTPUT
 [
 if test "$print_make_warning" = "true"; then

hadrian/src/Rules/SourceDist.hs

@@ -29,8 +29,6 @@ sourceDistRules = alternatives $ do
       archiveSourceTree prepareTree
     "GIT_COMMIT_ID" %> \fname ->
         writeFileChanged fname =<< setting ProjectGitCommitId
-    "VERSION" %> \fname ->
-        writeFileChanged fname =<< setting ProjectVersion
 
     -- Rules to download mingw tarballs
     let mingw_tarballs_stamp = "ghc-tarballs/mingw-w64/.mingw-w64.download.stamp"
@@ -120,7 +118,6 @@ prepareTree dest = do
     out <- askWithResources [] (target (vanillaContext Stage1 compiler) (Git ListFiles) [] [])
     top <- topDirectory
     let files = ["GIT_COMMIT_ID", "VERSION"] ++ getFiles out
-    need ["GIT_COMMIT_ID", "VERSION"]
     forM_ files $ \source -> do
       let target = dest -/- source
       copyFileSourceDist (top -/- source) target