indent: fix darwin build

pkgs/development/tools/misc/indent/darwin.patch

@@ -0,0 +1,15 @@
+diff --git a/config.h.in b/config.h.in
+index 07e6fce..0c57e2a 100644
+--- a/config.h.in
++++ b/config.h.in
+@@ -432,8 +432,8 @@
+ # endif
+ # define _GL_EXTERN_INLINE extern
+ #else
+-# define _GL_INLINE static _GL_UNUSED
+-# define _GL_EXTERN_INLINE static _GL_UNUSED
++# define _GL_INLINE static
++# define _GL_EXTERN_INLINE static
+ #endif
+ 
+ #if 4 < __GNUC__ + (6 <= __GNUC_MINOR__)

pkgs/development/tools/misc/indent/default.nix

@@ -8,11 +8,12 @@ stdenv.mkDerivation rec {
     sha256 = "12xvcd16cwilzglv9h7sgh4h1qqjd1h8s48ji2dla58m4706hzg7";
   };
 
+  patches = [ ./darwin.patch ];
+
   buildInputs = [ texinfo ];
 
-  postPatch = stdenv.lib.optionalString stdenv.isDarwin ''
-    sed -i 's|#include <malloc.h>|#include <malloc/malloc.h>|' ./man/texinfo2man.c
-  '';
+  NIX_CFLAGS_COMPILE = stdenv.lib.optionalString stdenv.cc.isClang
+    "-Wno-implicit-function-declaration";
 
   hardeningDisable = [ "format" ];