Rework how iOS does linking (#8127)

iOS has some particular constraints about how applications can be built:

 * We must generate a static library (.a) since XCode does the final
   link.
 * We need to carefully give the right set of arguments to libtool in
   the case we're generating an archive.
 * Dynamic linking isn't supported.
 * It can only be done on OS X.

This patch cleans up all of the above. We add a new flag `-staticlib`
(only supported on Darwin) that allows us to produce archive files using
libtool, and a -pgmlibtool flag to control which 'libtool' executable to
use.

This fixes #8127. I believe this is the last piece missing from the iOS
cross compiler.

Authored-by: Luke Iannini <lukexi@me.com>
Authored-by: Maxwell Swadling <maxwellswadling@gmail.com>
Authored-by: Stephen Blackheath <...@blacksapphire.com>
Signed-off-by: Austin Seipp <aseipp@pobox.com>

9 files changed, 144 insertions, 48 deletions

diff --git a/aclocal.m4 b/aclocal.m4
index e742e907d6..7e555446a1 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -464,6 +464,7 @@ AC_DEFUN([FP_SETTINGS],
         SettingsPerlCommand="$PerlCmd"
         SettingsDllWrapCommand="/bin/false"
         SettingsWindresCommand="/bin/false"
+        SettingsLibtoolCommand="libtool"
         SettingsTouchCommand='touch'
         if test -z "$LlcCmd"
         then
@@ -490,6 +491,7 @@ AC_DEFUN([FP_SETTINGS],
     AC_SUBST(SettingsPerlCommand)
     AC_SUBST(SettingsDllWrapCommand)
     AC_SUBST(SettingsWindresCommand)
+    AC_SUBST(SettingsLibtoolCommand)
     AC_SUBST(SettingsTouchCommand)
     AC_SUBST(SettingsLlcCommand)
     AC_SUBST(SettingsOptCommand)
diff --git a/compiler/main/DriverPipeline.hs b/compiler/main/DriverPipeline.hs
index c005a46873..9f279e0065 100644
--- a/compiler/main/DriverPipeline.hs
+++ b/compiler/main/DriverPipeline.hs
@@ -59,7 +59,7 @@ import System.Directory
 import System.FilePath
 import System.IO
 import Control.Monad
-import Data.List        ( isSuffixOf )
+import Data.List        ( isSuffixOf, isPrefixOf )
 import Data.Maybe
 import System.Environment
 import Data.Char
@@ -295,6 +295,9 @@ link NoLink _ _ _
 link LinkBinary dflags batch_attempt_linking hpt
    = link' dflags batch_attempt_linking hpt
 
+link LinkStaticLib dflags batch_attempt_linking hpt
+   = link' dflags batch_attempt_linking hpt
+
 link LinkDynLib dflags batch_attempt_linking hpt
    = link' dflags batch_attempt_linking hpt
 
@@ -311,6 +314,10 @@ link' dflags batch_attempt_linking hpt
    | batch_attempt_linking
    = do
         let
+            staticLink = case ghcLink dflags of
+                          LinkStaticLib -> True
+                          _ -> platformBinariesAreStaticLibs (targetPlatform dflags)
+
             home_mod_infos = eltsUFM hpt
 
             -- the packages we depend on
@@ -330,9 +337,9 @@ link' dflags batch_attempt_linking hpt
         let getOfiles (LM _ _ us) = map nameOfObject (filter isObject us)
             obj_files = concatMap getOfiles linkables
 
-            exe_file = exeFileName dflags
+            exe_file = exeFileName staticLink dflags
 
-        linking_needed <- linkingNeeded dflags linkables pkg_deps
+        linking_needed <- linkingNeeded dflags staticLink linkables pkg_deps
 
         if not (gopt Opt_ForceRecomp dflags) && not linking_needed
            then do debugTraceMsg dflags 2 (text exe_file <+> ptext (sLit "is up to date, linking not required."))
@@ -343,9 +350,10 @@ link' dflags batch_attempt_linking hpt
 
         -- Don't showPass in Batch mode; doLink will do that for us.
         let link = case ghcLink dflags of
-                LinkBinary  -> linkBinary
-                LinkDynLib  -> linkDynLibCheck
-                other       -> panicBadLink other
+                LinkBinary    -> linkBinary
+                LinkStaticLib -> linkStaticLibCheck
+                LinkDynLib    -> linkDynLibCheck
+                other         -> panicBadLink other
         link dflags obj_files pkg_deps
 
         debugTraceMsg dflags 3 (text "link: done")
@@ -359,12 +367,12 @@ link' dflags batch_attempt_linking hpt
         return Succeeded
 
 
-linkingNeeded :: DynFlags -> [Linkable] -> [PackageId] -> IO Bool
-linkingNeeded dflags linkables pkg_deps = do
+linkingNeeded :: DynFlags -> Bool -> [Linkable] -> [PackageId] -> IO Bool
+linkingNeeded dflags staticLink linkables pkg_deps = do
         -- if the modification time on the executable is later than the
         -- modification times on all of the objects and libraries, then omit
         -- linking (unless the -fforce-recomp flag was given).
-  let exe_file = exeFileName dflags
+  let exe_file = exeFileName staticLink dflags
   e_exe_time <- tryIO $ getModificationUTCTime exe_file
   case e_exe_time of
     Left _  -> return True
@@ -482,10 +490,11 @@ doLink dflags stop_phase o_files
 
   | otherwise
   = case ghcLink dflags of
-        NoLink     -> return ()
-        LinkBinary -> linkBinary      dflags o_files []
-        LinkDynLib -> linkDynLibCheck dflags o_files []
-        other      -> panicBadLink other
+        NoLink        -> return ()
+        LinkBinary    -> linkBinary         dflags o_files []
+        LinkStaticLib -> linkStaticLibCheck dflags o_files []
+        LinkDynLib    -> linkDynLibCheck    dflags o_files []
+        other         -> panicBadLink other
 
 
 -- ---------------------------------------------------------------------------
@@ -1770,11 +1779,14 @@ getHCFilePackages filename =
 -- the packages.
 
 linkBinary :: DynFlags -> [FilePath] -> [PackageId] -> IO ()
-linkBinary dflags o_files dep_packages = do
+linkBinary = linkBinary' False
+
+linkBinary' :: Bool -> DynFlags -> [FilePath] -> [PackageId] -> IO ()
+linkBinary' staticLink dflags o_files dep_packages = do
     let platform = targetPlatform dflags
         mySettings = settings dflags
         verbFlags = getVerbFlags dflags
-        output_fn = exeFileName dflags
+        output_fn = exeFileName staticLink dflags
 
     -- get the full list of packages to link with, by combining the
     -- explicit packages with the auto packages and all of their
@@ -1815,13 +1827,15 @@ linkBinary dflags o_files dep_packages = do
     extraLinkObj <- mkExtraObjToLinkIntoBinary dflags
     noteLinkObjs <- mkNoteObjsToLinkIntoBinary dflags dep_packages
 
-    pkg_link_opts <- if platformBinariesAreStaticLibs platform
-                     then -- If building an executable really means
-                          -- making a static library (e.g. iOS), then
-                          -- we don't want the options (like -lm)
-                          -- that getPackageLinkOpts gives us. #7720
-                          return []
-                     else getPackageLinkOpts dflags dep_packages
+    pkg_link_opts <- do
+        (package_hs_libs, extra_libs, other_flags) <- getPackageLinkOpts dflags dep_packages
+        return $ if staticLink
+            then package_hs_libs -- If building an executable really means making a static
+                                 -- library (e.g. iOS), then we only keep the -l options for
+                                 -- HS packages, because libtool doesn't accept other options.
+                                 -- In the case of iOS these need to be added by hand to the
+                                 -- final link in Xcode.
+            else package_hs_libs ++ extra_libs ++ other_flags
 
     pkg_framework_path_opts <-
         if platformUsesFrameworks platform
@@ -1869,14 +1883,17 @@ linkBinary dflags o_files dep_packages = do
             let os = platformOS (targetPlatform dflags)
             in if os == OSOsf3 then ["-lpthread", "-lexc"]
                else if os `elem` [OSMinGW32, OSFreeBSD, OSOpenBSD,
-                                  OSNetBSD, OSHaiku, OSQNXNTO]
+                                  OSNetBSD, OSHaiku, OSQNXNTO, OSiOS]
                then []
                else ["-lpthread"]
          | otherwise               = []
 
     rc_objs <- maybeCreateManifest dflags output_fn
 
-    SysTools.runLink dflags (
+    let link = if staticLink
+                   then SysTools.runLibtool
+                   else SysTools.runLink
+    link dflags (
                        map SysTools.Option verbFlags
                       ++ [ SysTools.Option "-o"
                          , SysTools.FileOption "" output_fn
@@ -1899,6 +1916,7 @@ linkBinary dflags o_files dep_packages = do
                       --     ld: warning: could not create compact unwind for .LFB3: non-standard register 5 being saved in prolog
                       -- on x86.
                       ++ (if sLdSupportsCompactUnwind mySettings &&
+                             not staticLink &&
                              platformOS   platform == OSDarwin &&
                              platformArch platform `elem` [ArchX86, ArchX86_64]
                           then ["-Wl,-no_compact_unwind"]
@@ -1911,7 +1929,8 @@ linkBinary dflags o_files dep_packages = do
                       -- whether this is something we ought to fix, but
                       -- for now this flags silences them.
                       ++ (if platformOS   platform == OSDarwin &&
-                             platformArch platform == ArchX86
+                             platformArch platform == ArchX86 &&
+                             not staticLink
                           then ["-Wl,-read_only_relocs,suppress"]
                           else [])
 
@@ -1937,17 +1956,20 @@ linkBinary dflags o_files dep_packages = do
         throwGhcExceptionIO (InstallationError ("cannot move binary"))
 
 
-exeFileName :: DynFlags -> FilePath
-exeFileName dflags
+exeFileName :: Bool -> DynFlags -> FilePath
+exeFileName staticLink dflags
   | Just s <- outputFile dflags =
-      case platformOS (targetPlatform dflags) of 
+      case platformOS (targetPlatform dflags) of
           OSMinGW32 -> s <?.> "exe"
-          OSiOS     -> s <?.> "a"
-          _         -> s
+          _         -> if staticLink
+                         then s <?.> "a"
+                         else s
   | otherwise =
       if platformOS (targetPlatform dflags) == OSMinGW32
       then "main.exe"
-      else "a.out"
+      else if staticLink
+           then "liba.a"
+           else "a.out"
  where s <?.> ext | null (takeExtension s) = s <.> ext
                   | otherwise              = s
 
@@ -2014,6 +2036,13 @@ linkDynLibCheck dflags o_files dep_packages
 
     linkDynLib dflags o_files dep_packages
 
+linkStaticLibCheck :: DynFlags -> [String] -> [PackageId] -> IO ()
+linkStaticLibCheck dflags o_files dep_packages
+ = do
+    when (platformOS (targetPlatform dflags) `notElem` [OSiOS, OSDarwin]) $
+      throwGhcExceptionIO (ProgramError "Static archive creation only supported on Darwin/OS X/iOS")
+    linkBinary' True dflags o_files dep_packages
+
 -- -----------------------------------------------------------------------------
 -- Running CPP
 
diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index 64ec8be612..849d8a418c 100644
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -66,7 +66,7 @@ module DynFlags (
         ghcUsagePath, ghciUsagePath, topDir, tmpDir, rawSettings,
         extraGccViaCFlags, systemPackageConfig,
         pgm_L, pgm_P, pgm_F, pgm_c, pgm_s, pgm_a, pgm_l, pgm_dll, pgm_T,
-        pgm_sysman, pgm_windres, pgm_lo, pgm_lc,
+        pgm_sysman, pgm_windres, pgm_libtool, pgm_lo, pgm_lc,
         opt_L, opt_P, opt_F, opt_c, opt_a, opt_l,
         opt_windres, opt_lo, opt_lc,
 
@@ -798,6 +798,7 @@ data Settings = Settings {
   sPgm_T                 :: String,
   sPgm_sysman            :: String,
   sPgm_windres           :: String,
+  sPgm_libtool           :: String,
   sPgm_lo                :: (String,[Option]), -- LLVM: opt llvm optimiser
   sPgm_lc                :: (String,[Option]), -- LLVM: llc static compiler
   -- options for particular phases
@@ -853,6 +854,8 @@ pgm_sysman            :: DynFlags -> String
 pgm_sysman dflags = sPgm_sysman (settings dflags)
 pgm_windres           :: DynFlags -> String
 pgm_windres dflags = sPgm_windres (settings dflags)
+pgm_libtool           :: DynFlags -> String
+pgm_libtool dflags = sPgm_libtool (settings dflags)
 pgm_lo                :: DynFlags -> (String,[Option])
 pgm_lo dflags = sPgm_lo (settings dflags)
 pgm_lc                :: DynFlags -> (String,[Option])
@@ -948,6 +951,7 @@ data GhcLink
   | LinkInMemory        -- ^ Use the in-memory dynamic linker (works for both
                         --   bytecode and object code).
   | LinkDynLib          -- ^ Link objects into a dynamic lib (DLL on Windows, DSO on ELF platforms)
+  | LinkStaticLib       -- ^ Link objects into a static lib
   deriving (Eq, Show)
 
 isNoLink :: GhcLink -> Bool
@@ -2044,6 +2048,7 @@ dynamic_flags = [
   , Flag "pgml"           (hasArg (\f -> alterSettings (\s -> s { sPgm_l   = (f,[])})))
   , Flag "pgmdll"         (hasArg (\f -> alterSettings (\s -> s { sPgm_dll = (f,[])})))
   , Flag "pgmwindres"     (hasArg (\f -> alterSettings (\s -> s { sPgm_windres = f})))
+  , Flag "pgmlibtool"     (hasArg (\f -> alterSettings (\s -> s { sPgm_libtool = f})))
 
     -- need to appear before -optl/-opta to be parsed as LLVM flags.
   , Flag "optlo"          (hasArg (\f -> alterSettings (\s -> s { sOpt_lo  = f : sOpt_lo s})))
@@ -2078,6 +2083,7 @@ dynamic_flags = [
         -------- Linking ----------------------------------------------------
   , Flag "no-link"            (noArg (\d -> d{ ghcLink=NoLink }))
   , Flag "shared"             (noArg (\d -> d{ ghcLink=LinkDynLib }))
+  , Flag "staticlib"          (noArg (\d -> d{ ghcLink=LinkStaticLib }))
   , Flag "dynload"            (hasArg parseDynLibLoaderMode)
   , Flag "dylib-install-name" (hasArg setDylibInstallName)
     -- -dll-split is an internal flag, used only during the GHC build
diff --git a/compiler/main/GhcMake.hs b/compiler/main/GhcMake.hs
index c43b18a62a..8a14a0c132 100644
--- a/compiler/main/GhcMake.hs
+++ b/compiler/main/GhcMake.hs
@@ -294,7 +294,7 @@ load how_much = do
           let 
             main_mod = mainModIs dflags
             a_root_is_Main = any ((==main_mod).ms_mod) mod_graph
-            do_linking = a_root_is_Main || no_hs_main || ghcLink dflags == LinkDynLib
+            do_linking = a_root_is_Main || no_hs_main || ghcLink dflags == LinkDynLib || ghcLink dflags == LinkStaticLib
 
           when (ghcLink dflags == LinkBinary 
                 && isJust ofile && not do_linking) $
diff --git a/compiler/main/Packages.lhs b/compiler/main/Packages.lhs
index cc8dfe3eb7..fb832ff2e3 100644
--- a/compiler/main/Packages.lhs
+++ b/compiler/main/Packages.lhs
@@ -867,16 +867,19 @@ getPackageLibraryPath dflags pkgs =
 collectLibraryPaths :: [PackageConfig] -> [FilePath]
 collectLibraryPaths ps = nub (filter notNull (concatMap libraryDirs ps))
 
--- | Find all the link options in these and the preload packages
-getPackageLinkOpts :: DynFlags -> [PackageId] -> IO [String]
+-- | Find all the link options in these and the preload packages,
+-- returning (package hs lib options, extra library options, other flags)
+getPackageLinkOpts :: DynFlags -> [PackageId] -> IO ([String], [String], [String])
 getPackageLinkOpts dflags pkgs =
   collectLinkOpts dflags `fmap` getPreloadPackagesAnd dflags pkgs
 
-collectLinkOpts :: DynFlags -> [PackageConfig] -> [String]
-collectLinkOpts dflags ps = concat (map all_opts ps)
-  where
-        libs p     = packageHsLibs dflags p ++ extraLibraries p
-        all_opts p = map ("-l" ++) (libs p) ++ ldOptions p
+collectLinkOpts :: DynFlags -> [PackageConfig] -> ([String], [String], [String])
+collectLinkOpts dflags ps =
+    (
+        concatMap (map ("-l" ++) . packageHsLibs dflags) ps,
+        concatMap (map ("-l" ++) . extraLibraries) ps,
+        concatMap ldOptions ps
+    )
 
 packageHsLibs :: DynFlags -> PackageConfig -> [String]
 packageHsLibs dflags p = map (mkDynName . addSuffix) (hsLibraries p)
diff --git a/compiler/main/SysTools.lhs b/compiler/main/SysTools.lhs
index d43826a046..6fe29a99c4 100644
--- a/compiler/main/SysTools.lhs
+++ b/compiler/main/SysTools.lhs
@@ -15,7 +15,7 @@ module SysTools (
         runUnlit, runCpp, runCc, -- [Option] -> IO ()
         runPp,                   -- [Option] -> IO ()
         runSplit,                -- [Option] -> IO ()
-        runAs, runLink,          -- [Option] -> IO ()
+        runAs, runLink, runLibtool, -- [Option] -> IO ()
         runMkDLL,
         runWindres,
         runLlvmOpt,
@@ -261,6 +261,7 @@ initSysTools mbMinusB
            split_script  = installed cGHC_SPLIT_PGM
 
        windres_path <- getSetting "windres command"
+       libtool_path <- getSetting "libtool command"
 
        tmpdir <- getTemporaryDirectory
 
@@ -331,6 +332,7 @@ initSysTools mbMinusB
                     sPgm_T   = touch_path,
                     sPgm_sysman  = top_dir ++ "/ghc/rts/parallel/SysMan",
                     sPgm_windres = windres_path,
+                    sPgm_libtool = libtool_path,
                     sPgm_lo  = (lo_prog,[]),
                     sPgm_lc  = (lc_prog,[]),
                     -- Hans: this isn't right in general, but you can
@@ -717,6 +719,15 @@ runLink dflags args = do
   mb_env <- getGccEnv args2
   runSomethingFiltered dflags id "Linker" p args2 mb_env
 
+runLibtool :: DynFlags -> [Option] -> IO ()
+runLibtool dflags args = do
+  linkargs <- neededLinkArgs `fmap` getLinkerInfo dflags
+  let args1      = map Option (getOpts dflags opt_l)
+      args2      = [Option "-static"] ++ args1 ++ args ++ linkargs
+      libtool    = pgm_libtool dflags    
+  mb_env <- getGccEnv args2
+  runSomethingFiltered dflags id "Linker" libtool args2 mb_env
+
 runMkDLL :: DynFlags -> [Option] -> IO ()
 runMkDLL dflags args = do
   let (p,args0) = pgm_dll dflags
@@ -1220,7 +1231,8 @@ linkDynLib dflags0 o_files dep_packages
                           pkgs
                       _ ->
                           filter ((/= rtsPackageId) . packageConfigId) pkgs
-    let pkg_link_opts = collectLinkOpts dflags pkgs_no_rts
+    let pkg_link_opts = let (package_hs_libs, extra_libs, other_flags) = collectLinkOpts dflags pkgs_no_rts
+                        in  package_hs_libs ++ extra_libs ++ other_flags
 
         -- probably _stub.o files
     let extra_ld_inputs = ldInputs dflags
@@ -1315,6 +1327,7 @@ linkDynLib dflags0 o_files dep_packages
                  ++ map Option pkg_lib_path_opts
                  ++ map Option pkg_link_opts
               )
+        OSiOS -> throwGhcExceptionIO (ProgramError "dynamic libraries are not supported on iOS target")
         _ -> do
             -------------------------------------------------------------------
             -- Making a DSO
diff --git a/docs/users_guide/flags.xml b/docs/users_guide/flags.xml
index ba4b0b13b0..282ca7624b 100644
--- a/docs/users_guide/flags.xml
+++ b/docs/users_guide/flags.xml
@@ -2085,6 +2085,15 @@
             <entry>-</entry>
           </row>
           <row>
+            <entry><option>-staticlib</option></entry>
+            <entry>On Darwin/OS X/iOS only, generate a standalone static library 
+              (as opposed to an executable). 
+              This is the usual way to compile for iOS.
+              </entry>
+            <entry>dynamic</entry>
+            <entry>-</entry>
+          </row>
+          <row>
             <entry><option>-fPIC</option></entry>
             <entry>Generate position-independent code (where available)</entry>
             <entry>dynamic</entry>
@@ -2105,14 +2114,14 @@
           </row>
           <row>
             <entry><option>-framework</option> <replaceable>name</replaceable></entry>
-            <entry>On Darwin/MacOS X only, link in the framework <replaceable>name</replaceable>.
+            <entry>On Darwin/OS X/iOS only, link in the framework <replaceable>name</replaceable>.
               This option corresponds to the <option>-framework</option> option for Apple's Linker.</entry>
             <entry>dynamic</entry>
             <entry>-</entry>
           </row>
           <row>
             <entry><option>-framework-path</option> <replaceable>name</replaceable></entry>
-            <entry>On Darwin/MacOS X only, add <replaceable>dir</replaceable> to the list of
+            <entry>On Darwin/OS X/iOS only, add <replaceable>dir</replaceable> to the list of
               directories searched for frameworks.
               This option corresponds to the <option>-F</option> option for Apple's Linker.</entry>
             <entry>dynamic</entry>
@@ -2223,7 +2232,7 @@
             <entry>Set the install name (via <literal>-install_name</literal> passed to Apple's
               linker), specifying the full install path of the library file. Any libraries
               or executables that link with it later will pick up that path as their
-              runtime search location for it. (Darwin/MacOS X only)</entry>
+              runtime search location for it. (Darwin/OS X only)</entry>
             <entry>dynamic</entry>
             <entry>-</entry>
           </row>
@@ -2351,6 +2360,13 @@
             <entry>dynamic</entry>
             <entry>-</entry>
           </row>
+          <row>
+            <entry><option>-pgmlibtool</option> <replaceable>cmd</replaceable></entry>
+            <entry>Use <replaceable>cmd</replaceable> as the command for libtool 
+              (with <option>-staticlib</option> only).</entry>
+            <entry>dynamic</entry>
+            <entry>-</entry>
+          </row>
         </tbody>
       </tgroup>
     </informaltable>
diff --git a/docs/users_guide/phases.xml b/docs/users_guide/phases.xml
index 90489e84d2..acb53a73d9 100644
--- a/docs/users_guide/phases.xml
+++ b/docs/users_guide/phases.xml
@@ -137,6 +137,17 @@
               linkend="options-linker" />.</para>
         </listitem>
       </varlistentry>
+
+      <varlistentry>
+        <term>
+          <option>-pgmlibtool</option> <replaceable>cmd</replaceable>
+          <indexterm><primary><option>-pgmlibtool</option></primary></indexterm>
+        </term>
+        <listitem>
+          <para>Use <replaceable>cmd</replaceable> as the libtool command 
+          (when using <option>-staticlib</option> only).</para>
+        </listitem>
+      </varlistentry>
     </variablelist>
   </sect2>
 
@@ -721,7 +732,7 @@ $ cat foo.hspp</screen>
           <indexterm><primary><option>-framework</option></primary></indexterm>
         </term>
         <listitem>
-          <para>On Darwin/MacOS X only, link in the framework <replaceable>name</replaceable>.
+          <para>On Darwin/OS X/iOS only, link in the framework <replaceable>name</replaceable>.
           This option corresponds to the <option>-framework</option> option for Apple's Linker.
           Please note that frameworks and packages are two different things - frameworks don't
           contain any haskell code. Rather, they are Apple's way of packaging shared libraries.
@@ -733,6 +744,21 @@ $ cat foo.hspp</screen>
 
       <varlistentry>
         <term>
+          <option>-staticlib</option>
+          <indexterm><primary><option>-staticlib</option></primary></indexterm>
+        </term>
+        <listitem>
+          <para>On Darwin/OS X/iOS only, link all passed files into a static library suitable
+          for linking into an iOS (when using a cross-compiler) or Mac Xcode project. To control
+          the name, use the <option>-o</option> <replaceable>name</replaceable> option as usual.
+          The default name is <literal>liba.a</literal>.
+          This should nearly always be passed when compiling for iOS with a cross-compiler.
+          </para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term>
           <option>-L</option><replaceable>dir</replaceable>
           <indexterm><primary><option>-L</option></primary></indexterm>
         </term>
@@ -749,7 +775,7 @@ $ cat foo.hspp</screen>
           <indexterm><primary><option>-framework-path</option></primary></indexterm>
         </term>
         <listitem>
-          <para>On Darwin/MacOS X only, prepend the directory <replaceable>dir</replaceable> to
+          <para>On Darwin/OS X/iOS only, prepend the directory <replaceable>dir</replaceable> to
           the framework directories path. This option corresponds to the <option>-F</option>
           option for Apple's Linker (<option>-F</option> already means something else for GHC).</para>
         </listitem>
@@ -1189,7 +1215,7 @@ $ cat foo.hspp</screen>
           </indexterm>
         </term>
         <listitem>
-          <para>On Darwin/MacOS X, dynamic libraries are stamped at build time with an
+          <para>On Darwin/OS X, dynamic libraries are stamped at build time with an
               "install name", which is the ultimate install path of the library file.
               Any libraries or executables that subsequently link against it will pick
               up that path as their runtime search location for it. By default, ghc sets
diff --git a/settings.in b/settings.in
index 25699acc57..9f9654c689 100644
--- a/settings.in
+++ b/settings.in
@@ -14,6 +14,7 @@
  ("touch command", "@SettingsTouchCommand@"),
  ("dllwrap command", "@SettingsDllWrapCommand@"),
  ("windres command", "@SettingsWindresCommand@"),
+ ("libtool command", "@SettingsLibtoolCommand@"),
  ("perl command", "@SettingsPerlCommand@"),
  ("target os", "@HaskellTargetOs@"),
  ("target arch", "@HaskellTargetArch@"),