Delete casts to off_t and size_t that are implied by assignments

or prototypes.  Ditto for some of the char* and void* casts too.
verified no change to instructions on ILP32 (i386) and LP64 (amd64)
ok natano@ abluhm@ deraadt@ millert@

src/lib/libc/hash/helper.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: helper.c,v 1.15 2015/11/01 03:45:29 guenther Exp $ */
+/*	$OpenBSD: helper.c,v 1.16 2016/09/21 04:38:57 guenther Exp $ */
 
 /*
  * Copyright (c) 2000 Poul-Henning Kamp <phk@FreeBSD.org>
@@ -82,7 +82,7 @@ HASHFileChunk(const char *filename, char *buf, off_t off, off_t len)
 	}
 
 	while ((nr = read(fd, buffer, MINIMUM(sizeof(buffer), len))) > 0) {
-		HASHUpdate(&ctx, buffer, (size_t)nr);
+		HASHUpdate(&ctx, buffer, nr);
 		if (len > 0 && (len -= nr) == 0)
 			break;
 	}
@@ -97,7 +97,7 @@ DEF_WEAK(HASHFileChunk);
 char *
 HASHFile(const char *filename, char *buf)
 {
-	return (HASHFileChunk(filename, buf, (off_t)0, (off_t)0));
+	return (HASHFileChunk(filename, buf, 0, 0));
 }
 DEF_WEAK(HASHFile);
 

src/lib/libc/stdlib/malloc.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: malloc.c,v 1.196 2016/09/18 13:46:28 otto Exp $	*/
+/*	$OpenBSD: malloc.c,v 1.197 2016/09/21 04:38:56 guenther Exp $	*/
 /*
  * Copyright (c) 2008, 2010, 2011, 2016 Otto Moerbeek <otto@drijf.net>
  * Copyright (c) 2012 Matthew Dempsky <matthew@openbsd.org>
@@ -83,14 +83,14 @@
 #define SOME_JUNK		0xd0	/* as in "Duh" :-) */
 #define SOME_FREEJUNK		0xdf
 
-#define MMAP(sz)	mmap(NULL, (size_t)(sz), PROT_READ | PROT_WRITE, \
-    MAP_ANON | MAP_PRIVATE, -1, (off_t) 0)
+#define MMAP(sz)	mmap(NULL, (sz), PROT_READ | PROT_WRITE, \
+    MAP_ANON | MAP_PRIVATE, -1, 0)
 
-#define MMAPA(a,sz)	mmap((a), (size_t)(sz), PROT_READ | PROT_WRITE, \
-    MAP_ANON | MAP_PRIVATE, -1, (off_t) 0)
+#define MMAPA(a,sz)	mmap((a), (sz), PROT_READ | PROT_WRITE, \
+    MAP_ANON | MAP_PRIVATE, -1, 0)
 
-#define MQUERY(a, sz)	mquery((a), (size_t)(sz), PROT_READ | PROT_WRITE, \
-    MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, (off_t)0)
+#define MQUERY(a, sz)	mquery((a), (sz), PROT_READ | PROT_WRITE, \
+    MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, 0)
 
 struct region_info {
 	void *p;		/* page; low bits used to mark chunks */

src/lib/libc/stdlib/setenv.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: setenv.c,v 1.18 2016/04/25 21:36:04 millert Exp $ */
+/*	$OpenBSD: setenv.c,v 1.19 2016/09/21 04:38:56 guenther Exp $ */
 /*
  * Copyright (c) 1987 Regents of the University of California.
  * All rights reserved.
@@ -141,7 +141,7 @@ setenv(const char *name, const char *value, int rewrite)
 		environ[cnt + 1] = NULL;
 	}
 	if (!(environ[offset] =			/* name + `=' + value */
-	    malloc((size_t)((int)(np - name) + l_value + 2))))
+	    malloc((int)(np - name) + l_value + 2)))
 		return (-1);
 	for (C = environ[offset]; (*C = *name++) && *C != '='; ++C)
 		;