patch 9.0.1964: xattr support fails to build on MacOS X

Problem:  xattr support fails to build on MacOS X
Solution: Disable xattr support for MacOS X

MacOS X uses the same headers and functions sys/xattr.h but the function
signatures for xattr support are much different, so building fails.

So let's for now disable xattr support there.

closes: #13230
closes: #13232

Signed-off-by: Christian Brabandt <cb@256bit.org>

src/feature.h

@@ -1177,9 +1177,9 @@
 #endif
 
 /*
- * XATTR support
+ * currently Unix only: XATTR support
  */
 
-#if defined(FEAT_NORMAL) && defined(HAVE_XATTR)
+#if defined(FEAT_NORMAL) && defined(HAVE_XATTR) && !defined(MACOS_X)
 # define FEAT_XATTR
 #endif

src/os_unix.c

@@ -37,7 +37,6 @@ static int selinux_enabled = -1;
 
 #ifdef FEAT_XATTR
 # include <sys/xattr.h>
-# define XATTR_VAL_LEN 1024
 #endif
 
 #ifdef HAVE_SMACK

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1964,
 /**/
     1963,
 /**/