Added section numbers to page xrefs

man3/atexit.3

@@ -56,7 +56,7 @@ When a child process is created via
 .BR fork (2),
 it inherits copies of its parents registrations.
 Upon a successful call to one of the
-.BR exec ()
+.BR exec (3)
 functions,
 all registrations are removed.
 .SH "RETURN VALUE"

man3/errno.3

@@ -437,7 +437,7 @@ Timer expired
 (POSIX.1 (XSI STREAMS option))
 .sp
 (POSIX.1 says "STREAM
-.BR ioctl ()
+.BR ioctl (2)
 timeout")
 .TP
 .BR ETIMEDOUT

man3/fgetwc.3

@@ -30,7 +30,7 @@ The
 .BR fgetwc ()
 function is the wide-character equivalent
 of the
-.BR fgetc ()
+.BR fgetc (3)
 function.
 It reads a wide character from \fIstream\fP and returns it.
 If the end of stream is reached, or if \fIferror(stream)\fP becomes true,

man3/fgetws.3

@@ -26,7 +26,7 @@ The
 .BR fgetws ()
 function is the wide-character equivalent
 of the
-.BR fgets ()
+.BR fgets (3)
 function.
 It reads a string of at most \fIn-1\fP wide characters into the
 wide-character array pointed to by \fIws\fP, and adds a terminating L'\\0'