Make Build/BuildVersion update embedded version number

This way, autobuilders can run it before building, in a tree where
git-annex was already built, and get the current git rev embedded in the
build.

Before, the version number only updated when the setup program was run,
which was up to cabal and not on every build.

Build/BuildVersion.hs

@@ -1,6 +1,12 @@
-{- Outputs the version of git-annex that was built, for use by
- - autobuilders. Note that this includes the git rev. -}
+{- For use by autobuilders, this outputs the version of git-annex that
+ - is being built, and also updates the Build/Version file so the build
+ - will report the right version, including the current git rev. -}
+
+{-# OPTIONS_GHC -fno-warn-tabs #-}
 
 import Build.Version
 
-main = putStr =<< getVersion
+main = do
+	ver <- getVersion
+	writeVersion ver
+	putStr ver

Build/Configure.hs

@@ -1,4 +1,4 @@
-{- Checks system configuration and generates SysConfig. -}
+{- Checks system configuration and generates Build/SysConfig and Build/Version. -}
 
 {-# OPTIONS_GHC -fno-warn-tabs #-}
 
@@ -12,15 +12,13 @@ import Utility.Env.Basic
 import qualified Git.Version
 import Utility.Directory
 
-import Control.Monad.IfElse
 import Control.Monad
 import Control.Applicative
 import Prelude
 
 tests :: [TestCase]
 tests =
-	[ TestCase "version" (Config "packageversion" . StringConfig <$> getVersion)
-	, TestCase "UPGRADE_LOCATION" getUpgradeLocation
+	[ TestCase "UPGRADE_LOCATION" getUpgradeLocation
 	, TestCase "git" $ testCmd "git" "git --version >/dev/null"
 	, TestCase "git version" getGitVersion
 	, testCp "cp_a" "-a"
@@ -120,6 +118,7 @@ run ts = do
 	case v of
 		Just "Android" -> writeSysConfig $ androidConfig config
 		_ -> writeSysConfig config
+	writeVersion =<< getVersion
 	cleanup
 
 {- Hard codes some settings to cross-compile for Android. -}

Build/Version.hs

@@ -1,4 +1,4 @@
-{- Package version determination, for configure script. -}
+{- Package version determination. -}
 
 {-# OPTIONS_GHC -fno-warn-tabs #-}
 
@@ -13,7 +13,6 @@ import Prelude
 
 import Utility.Monad
 import Utility.Exception
-import Utility.Directory
 
 type Version = String
 
@@ -33,7 +32,6 @@ getVersion = do
 	ifM (isReleaseBuild)
 		( return changelogversion
 		, catchDefaultIO changelogversion $ do
-			let major = takeWhile (/= '.') changelogversion
 			gitversion <- takeWhile (\c -> isAlphaNum c) <$> readProcess "sh"
 				[ "-c"
 				, "git log -n 1 --format=format:'%h'"
@@ -54,3 +52,18 @@ getChangelogVersion = do
 	return $ middle (words verline !! 1)
   where
 	middle = drop 1 . init
+
+writeVersion :: Version -> IO ()
+writeVersion = writeFile "Build/Version" . body
+  where
+	body ver = unlines $ concat
+		[ header
+		, ["packageversion :: String"]
+		, ["packageversion = \"" ++ ver ++ "\""]
+		, footer
+		]
+	header = [
+		  "{- Automatically generated. -}"
+		, ""
+		]
+	footer = []