select.2: Remove details of historical #include requirements

The POSIX situation has been the norm for a long time now,
and including ancient details overcomplicates the page.

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

man2/select.2

@@ -41,14 +41,8 @@ select, pselect, FD_CLR, FD_ISSET, FD_SET, FD_ZERO \-
 synchronous I/O multiplexing
 .SH SYNOPSIS
 .nf
-/* According to POSIX.1-2001, POSIX.1-2008 */
 .B #include <sys/select.h>
 .PP
-/* According to earlier standards */
-.B #include <sys/time.h>
-.B #include <sys/types.h>
-.B #include <unistd.h>
-.PP
 .BI "int select(int " nfds ", fd_set *" readfds ", fd_set *" writefds ,
 .BI "           fd_set *" exceptfds ", struct timeval *" timeout );
 .PP
@@ -56,8 +50,6 @@ synchronous I/O multiplexing
 .BI "int  FD_ISSET(int " fd ", fd_set *" set );
 .BI "void FD_SET(int " fd ", fd_set *" set );
 .BI "void FD_ZERO(fd_set *" set );
-
-.B #include <sys/select.h>
 .PP
 .BI "int pselect(int " nfds ", fd_set *" readfds ", fd_set *" writefds ,
 .BI "            fd_set *" exceptfds ", const struct timespec *" timeout ,
@@ -446,18 +438,6 @@ in the main program.
 or reading from a pipe that may be empty,
 nonblocking I/O is used when reading from and writing to the pipe.)
 .PP
-Concerning prototypes, the classical situation is that one should
-include
-.I <time.h>
-for
-.BR select ().
-The POSIX.1 situation is that one should include
-.I <sys/select.h>
-for
-.BR select ()
-and
-.BR pselect ().
-.PP
 Under glibc 2.0,
 .I <sys/select.h>
 gives the wrong prototype for
@@ -467,7 +447,6 @@ Under glibc 2.1 to 2.2.1, it gives
 when
 .B _GNU_SOURCE
 is defined.
-Since glibc 2.2.2, the requirements are as shown in the SYNOPSIS.
 .\"
 .SS Correspondence between select() and poll() notifications
 Within the Linux kernel source,
@@ -657,9 +636,7 @@ to a local variable and passing that variable to the system call.
 .EX
 #include <stdio.h>
 #include <stdlib.h>
-#include <sys/time.h>
-#include <sys/types.h>
-#include <unistd.h>
+#include <sys/select.h>
 
 int
 main(void)