Fix AC_FUNC_MMAP on CheriBSD

Problem reported by Brooks Davis in:
https://lists.gnu.org/r/autoconf/2023-12/msg00022.html
* lib/autoconf/functions.m4: Don’t unmap, since we
want to test remapping something already mapped,
and unmapping breaks on CheriBSD.

diff --git a/lib/autoconf/functions.m4 b/lib/autoconf/functions.m4
index 4cfb5142ce9e670b94d9f2d11ca88a99836f18b2..9b3f3c0207f567bd1500e6e85a423f776b59ee2d 100644 (file)
--- a/lib/autoconf/functions.m4
+++ b/lib/autoconf/functions.m4
@@ -1385,8 +1385,7 @@ main (void)
     if (*(data2 + i))
       return 7;
   close (fd2);
-  if (munmap (data2, pagesize))
-    return 8;
+  /* 'return 8;' not currently used.  */
 
   /* Next, try to mmap the file at a fixed address which already has
      something else allocated at it.  If we can, also make sure that