libutil: fix conditional for close_range availability

This check is wrong and would cause the close_range() function being called even when it's not available

Change-Id: Ide65b36830e705fe772196c37349873353622761
(cherry picked from commit df49d37b71)

meson.build

@@ -417,7 +417,7 @@ check_funcs = [
   'strsignal',
   'sysconf',
 ]
-if target_machine.kernel() in ['linux', 'freebsd']
+if is_linux or is_freebsd
   # musl does not have close_range as of 2024-08-10
   # patch: https://www.openwall.com/lists/musl/2024/08/01/9
   check_funcs += [ 'close_range' ]

src/libutil/file-descriptor.cc

@@ -228,7 +228,7 @@ void closeExtraFDs()
     auto closeRange = [](unsigned int first, unsigned int last, int flags) -> int {
       // musl does not have close_range as of 2024-08-10
       // patch: https://www.openwall.com/lists/musl/2024/08/01/9
-#ifdef HAVE_CLOSE_RANGE
+#if HAVE_CLOSE_RANGE
         return close_range(first, last, flags);
 #else
         return syscall(SYS_close_range, first, last, flags);