mount: Surround syslog.h with the config check

This lets bb mount build for limited targets without syslog.h,
as long as the parts using it like NFS are disabled.

Signed-off-by: Lauri Kasanen <cand@gmx.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

util-linux/mount.c

@@ -182,7 +182,9 @@
 //usage:       "Returns 0 for success, number of failed mounts for -a, or errno for one mount."
 
 #include <mntent.h>
+#if ENABLE_FEATURE_SYSLOG
 #include <syslog.h>
+#endif
 #include <sys/mount.h>
 // Grab more as needed from util-linux's mount/mount_constants.h
 #ifndef MS_DIRSYNC