Port NetBSD libc functions to Minix.

This patch contains changes to NetBSD libc code base to make it
compile and work on Minix. Some of them are due to actual NetBSD
libc bugs, as we're compiling it in non-reentrant mode and with
a.out support, something not exactly frequent in NetBSD.
Others are proper fixes to port it to Minix (mostly sa_len
parameter missing in socket and a few mmap from files).

lib/nbsd_libc/stdlib/malloc.c

@@ -65,8 +65,10 @@
 #       define malloc_pageshift         12U
 #       define malloc_minsize           16U
 #   endif
+#ifndef __minix
 #   define HAS_UTRACE
 #   define UTRACE_LABEL
+#endif /* __minix */
 
 #include <sys/cdefs.h>
 void utrace(struct ut *, int);
@@ -210,9 +212,11 @@ static size_t malloc_pagemask;
 #define INIT_MMAP()
 #endif
 
+#ifndef __minix
 #ifndef MADV_FREE
 #define MADV_FREE MADV_DONTNEED
 #endif
+#endif /* !__minix */
 
 /* Number of free pages we cache */
 static size_t malloc_cache = 16;
@@ -485,8 +489,10 @@ malloc_init(void)
 		case '<': malloc_cache   >>= 1; break;
 		case 'a': malloc_abort   = 0; break;
 		case 'A': malloc_abort   = 1; break;
+#ifndef __minix
 		case 'h': malloc_hint    = 0; break;
 		case 'H': malloc_hint    = 1; break;
+#endif /* !__minix */
 		case 'r': malloc_realloc = 0; break;
 		case 'R': malloc_realloc = 1; break;
 		case 'j': malloc_junk    = 0; break;
@@ -932,8 +938,10 @@ free_pages(void *ptr, size_t idx, struct pginfo *info)
     if (malloc_junk)
 	memset(ptr, SOME_JUNK, l);
 
+#ifndef __minix
     if (malloc_hint)
 	madvise(ptr, l, MADV_FREE);
+#endif /* !__minix */
 
     tail = (char *)ptr+l;