Add minimal LibC module

.gitignore

@@ -4,3 +4,4 @@ unversioned
 cabal.project.local
 .vscode/
 *.dll
+macros-recognized.log

hs-bindgen-libclang/src/HsBindgen/Clang/Args.hs

@@ -1,3 +1,5 @@
+{-# LANGUAGE LambdaCase #-}
+
 module HsBindgen.Clang.Args (
     ClangArgs(..)
   , CStandard(..)
@@ -15,6 +17,9 @@ import HsBindgen.Clang.Version
 
 -- | @libclang@ command line arguments
 --
+-- The default standard when one is not specified depends on the Clang version
+-- and has GNU extensions enabled.
+--
 -- TODO: <https://github.com/well-typed/hs-bindgen/issues/83> (also #10 and #71).
 -- We should support more of the command line arguments of @clang@.
 data ClangArgs = ClangArgs {
@@ -24,6 +29,9 @@ data ClangArgs = ClangArgs {
       -- | C standard
     , clangCStandard :: Maybe CStandard
 
+      -- | Enable GNU extensions when 'True'
+    , clangEnableGnu :: Bool
+
       -- | Other arguments
       --
       -- See https://clang.llvm.org/docs/ClangCommandLineReference.html
@@ -43,17 +51,18 @@ data ClangArgs = ClangArgs {
 -- We don't currently support @C2y@ because it requires @clang-19@ or later and
 -- we have no reliable way to test for that (see 'ClangVersion').
 data CStandard =
-    C23
-  | C17
-  | C11
+    C89
   | C99
-  | C89
-  deriving stock (Show, Eq)
+  | C11
+  | C17
+  | C23
+  deriving stock (Bounded, Enum, Eq, Ord, Show)
 
 defaultClangArgs :: ClangArgs
 defaultClangArgs = ClangArgs {
       clangTarget    = Nothing
     , clangCStandard = Nothing
+    , clangEnableGnu = False
     , clangOtherArgs = []
     }
 
@@ -66,28 +75,41 @@ fromClangArgs args = aux [
       ifGiven clangTarget $ \target ->
         return ["-target", target]
 
-    , ifGiven clangCStandard $ \cStandard ->
-        case cStandard of
-          C23 -> -- We can use @-std=c23@ in @clang-18@ or later, but we have no
-                 -- reliable way of testing for that.
-                 if clangVersion >= Clang9_or_10
-                   then return ["-std=c2x"]
-                   else throwError "C23 requires clang-9 or later"
-          C17 -> if clangVersion >= Clang6
-                   then return ["-std=c17"]
-                   else throwError "C17 requires clang-6 or later"
-          C11 -> if clangVersion == ClangOlderThan3_2
-                   then return ["-std=c1x"]
-                   else return ["-std=c11"]
-          C99 -> return ["-std=c99"]
-          C89 -> return ["-std=c89"]
+    , ifGiven clangCStandard $ \case
+        C89
+          | clangEnableGnu -> return ["-std=gnu89"]
+          | otherwise      -> return ["-std=c89"]
+        C99
+          | clangEnableGnu -> return ["-std=gnu99"]
+          | otherwise      -> return ["-std=c99"]
+        C11
+          | clangEnableGnu -> return $
+              if clangVersion == ClangOlderThan3_2
+                then ["-std=gnu1x"]
+                else ["-std=gnu11"]
+          | otherwise      -> return $
+              if clangVersion == ClangOlderThan3_2
+                then ["-std=c1x"]
+                else ["-std=c11"]
+        C17
+          | clangVersion < Clang6 -> throwError "C17 requires clang-6 or later"
+          | clangEnableGnu -> return ["-std=gnu17"]
+          | otherwise      -> return ["-std=c17"]
+        -- We can use @-std=c23@ in @clang-18@ or later, but we have no reliable
+        -- way of testing for that.
+        C23
+          | clangVersion < Clang9_or_10 ->
+              throwError "C23 requires clang-9 or later"
+          | clangEnableGnu -> return ["-std=gnu2x"]
+          | otherwise      -> return ["-std=c2x"]
 
     , return clangOtherArgs
     ]
   where
     ClangArgs{
         clangTarget
       , clangCStandard
+      , clangEnableGnu
       , clangOtherArgs
       } = args
 

hs-bindgen-patterns/hs-bindgen-patterns.cabal

@@ -36,16 +36,25 @@ library
   import:
       lang
   exposed-modules:
-      HsBindgen.Patterns
       HsBindgen.ConstantArray
+      HsBindgen.Patterns
       HsBindgen.Patterns.FlexibleArrayMember
+      HsBindgen.Patterns.LibC
   other-modules:
       HsBindgen.Patterns.Arithmetic
       HsBindgen.Patterns.Backtrace
       HsBindgen.Patterns.Enum.Bitfield
       HsBindgen.Patterns.Enum.Simple
+      HsBindgen.Patterns.LibC.Arch
   hs-source-dirs:
       src
+  if arch(x86_64)
+    hs-source-dirs: src-x86_64
+  else
+    if arch(aarch64)
+      hs-source-dirs: src-aarch64
+    else
+      buildable: False
   build-depends:
     , pretty-show >= 1.10 && < 1.11
     , vector ^>=0.13.2.0

hs-bindgen-patterns/src-aarch64/HsBindgen/Patterns/LibC/Arch.hs

@@ -0,0 +1,2 @@
+module HsBindgen.Patterns.LibC.Arch (
+  ) where

hs-bindgen-patterns/src-x86_64/HsBindgen/Patterns/LibC/Arch.hs

@@ -0,0 +1,2 @@
+module HsBindgen.Patterns.LibC.Arch (
+  ) where