random.4, sk98lin.4, vcs.4: ffix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man4/random.4

@@ -293,13 +293,15 @@ which only adds some
 data but does not increment the entropy count.
 The following structure is used:
 .IP
-.nf
-    struct rand_pool_info {
-        int    entropy_count;
-        int    buf_size;
-        __u32  buf[0];
-    };
-.fi
+.in +4n
+.EX
+struct rand_pool_info {
+    int    entropy_count;
+    int    buf_size;
+    __u32  buf[0];
+};
+.EE
+.in
 .IP
 Here
 .I entropy_count

man4/sk98lin.4

@@ -412,8 +412,8 @@ ConType | DupCap   AutoNeg   FlowCtrl   Role   Speed
 \fI10FD\fP    |  Full      Off       None     Auto   10
 .br
 \fI10HD\fP    |  Half      Off       None     Auto   10
-
 .fi
+.IP
 Stating any other port parameter together with this
 .I ConType
 parameter will result in a merged configuration of those settings.

man4/vcs.4

@@ -79,13 +79,15 @@ administrator can control access using filesystem permissions.
 .PP
 The devices for the first eight virtual consoles may be created by:
 .PP
-.nf
-    for x in 0 1 2 3 4 5 6 7 8; do
-        mknod \-m 644 /dev/vcs$x c 7 $x;
-        mknod \-m 644 /dev/vcsa$x c 7 $[$x+128];
-    done
-    chown root:tty /dev/vcs*
-.fi
+.in +4n
+.EX
+for x in 0 1 2 3 4 5 6 7 8; do
+    mknod \-m 644 /dev/vcs$x c 7 $x;
+    mknod \-m 644 /dev/vcsa$x c 7 $[$x+128];
+done
+chown root:tty /dev/vcs*
+.EE
+.in
 .PP
 No
 .BR ioctl (2)
@@ -121,7 +123,7 @@ This program displays the character and screen attributes under the
 cursor of the second virtual console, then changes the background color
 there:
 .PP
-.nf
+.EX
 #include <unistd.h>
 #include <stdlib.h>
 #include <stdio.h>
@@ -168,7 +170,7 @@ main(void)
     (void) write(fd, &attrib, 1);
     exit(EXIT_SUCCESS);
 }
-.fi
+.EE
 .SH SEE ALSO
 .BR ioctl_console (2),
 .BR tty (4),