Remove register keyword usage with prejudice.

Modern compilers are smarter when it comes to allocating register
usage.

usr.bin/tail/forward.c

@@ -269,8 +269,8 @@ rlines(fp, off, sbp)
 	long off;
 	struct stat *sbp;
 {
-	register off_t size;
-	register char *p;
+	off_t size;
+	char *p;
 	char *start;
 
 	if (!(size = sbp->st_size))

usr.bin/tail/read.c

@@ -65,11 +65,11 @@ static const char rcsid[] =
  */
 int
 bytes(fp, off)
-	register FILE *fp;
+	FILE *fp;
 	off_t off;
 {
-	register int ch, len, tlen;
-	register char *ep, *p, *t;
+	int ch, len, tlen;
+	char *ep, *p, *t;
 	int wrap;
 	char *sp;
 
@@ -133,7 +133,7 @@ bytes(fp, off)
  */
 int
 lines(fp, off)
-	register FILE *fp;
+	FILE *fp;
 	off_t off;
 {
 	struct {
@@ -141,8 +141,8 @@ lines(fp, off)
 		u_int len;
 		char *l;
 	} *lines;
-	register int ch;
-	register char *p;
+	int ch;
+	char *p;
 	int blen, cnt, recno, wrap;
 	char *sp;
 

usr.bin/tail/reverse.c

@@ -110,13 +110,13 @@ reverse(fp, style, off, sbp)
 static void
 r_reg(fp, style, off, sbp)
 	FILE *fp;
-	register enum STYLE style;
+	enum STYLE style;
 	long off;
 	struct stat *sbp;
 {
-	register off_t size;
-	register int llen;
-	register char *p;
+	off_t size;
+	int llen;
+	char *p;
 	char *start;
 
 	if (!(size = sbp->st_size))
@@ -175,9 +175,9 @@ static void
 r_buf(fp)
 	FILE *fp;
 {
-	register BF *mark, *tl, *tr;
-	register int ch, len, llen;
-	register char *p;
+	BF *mark, *tl, *tr;
+	int ch, len, llen;
+	char *p;
 	off_t enomem;
 
 #define	BSZ	(128 * 1024)

usr.bin/tail/tail.c

@@ -223,7 +223,7 @@ static void
 obsolete(argv)
 	char *argv[];
 {
-	register char *ap, *p, *t;
+	char *ap, *p, *t;
 	size_t len;
 	char *start;