sys/param.h: Cleanup.

* Minor tweaks to POSIX sys/param.h for style.

 * Don't redefine alignment macros in BSD sys/param.h even conditionally.
   And add a few more macros from the real BSD sys/param.h, for convenience.
   (Most of these are also declared in musl and glibc's sys/param.h)

headers/posix/sys/param.h

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 Haiku, Inc. All Rights Reserved.
+ * Copyright 2002-2024, Haiku, Inc. All rights reserved.
  * Distributed under the terms of the MIT License.
  */
 #ifndef _SYS_PARAM_H
@@ -9,11 +9,13 @@
 #include <limits.h>
 
 
+#define MAXHOSTNAMELEN	(256)		/* maximum possible length of this machine's hostname */
+
 #define MAXPATHLEN      PATH_MAX
 #define MAXSYMLINKS		SYMLOOP_MAX
-
 #define NOFILE          OPEN_MAX
 
+
 #ifndef MIN
 #	define MIN(a,b) (((a) < (b)) ? (a) : (b))
 #endif
@@ -22,12 +24,7 @@
 #endif
 
 #define _ALIGNBYTES	(sizeof(long) - 1)
-#define _ALIGN(p) \
-	(((u_long)(p) + _ALIGNBYTES) &~ _ALIGNBYTES)
+#define _ALIGN(p)	(((u_long)(p) + _ALIGNBYTES) &~ _ALIGNBYTES)
 
-/* maximum possible length of this machine's hostname */
-#ifndef MAXHOSTNAMELEN
-#	define MAXHOSTNAMELEN 256
-#endif
 
 #endif	/* _SYS_PARAM_H */