Cleanup after non-Linux code removal.

Conditions such as defined(LINUX) are always true now,
defined(FREEBSD) etc are always false.
When if directive has them as subexpressions, it can be simplified.
Another trivial changes here are fixes for directive indentation.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/mem.c b/mem.c
index e8bad07..252486a 100644
--- a/mem.c
+++ b/mem.c
@@ -37,13 +37,13 @@
 #include <asm/mman.h>
 #include <sys/mman.h>
 
-#if defined(LINUX) && defined(I386)
+#if defined(I386)
 # include <asm/ldt.h>
 # ifdef HAVE_STRUCT_USER_DESC
 #  define modify_ldt_ldt_s user_desc
 # endif
 #endif
-#if defined(LINUX) && defined(SH64)
+#if defined(SH64)
 # include <asm/page.h>	    /* for PAGE_SHIFT */
 #endif
 
@@ -299,7 +299,7 @@
 	 * from pages to bytes. See test/mmap_offset_decode.c
 	 * Why SH64 and i386 are handled differently?
 	 */
-#if defined(LINUX) && defined(SH64)
+#if defined(SH64)
 	/*
 	 * Old mmap differs from new mmap in specifying the
 	 * offset in units of bytes rather than pages.  We
@@ -325,7 +325,7 @@
 sys_mmap64(struct tcb *tcp)
 {
 	if (entering(tcp)) {
-#if !defined(LINUX) || defined(ALPHA)
+#if defined(ALPHA)
 		long *u_arg = tcp->u_arg;
 #else
 		long u_arg[7];
@@ -354,7 +354,7 @@
 		tprints(", ");
 		printfd(tcp, u_arg[4]);
 		/* offset */
-#if !defined(LINUX) || defined(ALPHA)
+#if defined(ALPHA)
 		printllval(tcp, ", %#llx", 5);
 #else
 		/* NOTE: not verified that [5] and [6] should be used.
@@ -574,7 +574,7 @@
 	return 0;
 }
 
-#if defined(ALPHA) || defined(FREEBSD) || defined(IA64) || defined(SUNOS4) || defined(SVR4) || defined(SPARC) || defined(SPARC64)
+#if defined(ALPHA) || defined(IA64) || defined(SPARC) || defined(SPARC64)
 int
 sys_getpagesize(struct tcb *tcp)
 {
@@ -582,9 +582,9 @@
 		return RVAL_HEX;
 	return 0;
 }
-#endif /* ALPHA || FREEBSD || IA64 || SUNOS4 || SVR4 */
+#endif
 
-#if defined(LINUX) && defined(__i386__)
+#if defined(__i386__)
 void
 print_ldt_entry(struct modify_ldt_ldt_s *ldt_entry)
 {
@@ -676,10 +676,9 @@
 	return 0;
 
 }
-#endif /* LINUX && __i386__ */
+#endif /* __i386__ */
 
-#if defined(LINUX) && defined(M68K)
-
+#if defined(M68K)
 int
 sys_set_thread_area(struct tcb *tcp)
 {
@@ -910,7 +909,7 @@
 	return 0;
 }
 
-#if defined(LINUX) && defined(POWERPC)
+#if defined(POWERPC)
 int
 sys_subpage_prot(struct tcb *tcp)
 {