ioctl: Fix for Haiku

[Bruno Haible]

On Haiku (a recent one), the gnulib module 'ioctl' produces a compilation
error:

In file included from /boot/system/develop/headers/posix/sys/types.h:127:0,
                 from ./sys/types.h:28,
                 from ../../gllib/poll.c:29:
./sys/ioctl.h:484:1: error: conflicting types for 'ioctl'
 _GL_FUNCDECL_SYS (ioctl, int,
 ^
In file included from /boot/system/develop/headers/bsd/unistd.h:9:0,
                 from ./unistd.h:40,
                 from ../../gllib/poll.c:51:
/boot/system/develop/headers/posix/unistd.h:182:13: note: previous declaration 
of 'ioctl' was here
 extern int  ioctl(int fd, unsigned long op, ...);
             ^

The reason is that ioctl() is defined with a non-POSIX signature, and our
m4/ioctl.m4 fails to detect it. This fixes it.


2017-10-28  Bruno Haible  <address@hidden>

        ioctl: Override non-POSIX declaration on Haiku.
        * m4/ioctl.m4 (gl_FUNC_IOCTL): Include also <unistd.h>.
        * lib/sys_ioctl.in.h: Add comment about Haiku.
        * doc/posix-functions/ioctl.texi: Mention Haiku problem.
        * doc/glibc-headers/sys_ioctl.texi: Likewise.

diff --git a/m4/ioctl.m4 b/m4/ioctl.m4
index 30209dd..57ca2a3 100644
--- a/m4/ioctl.m4
+++ b/m4/ioctl.m4
@@ -1,4 +1,4 @@
-# ioctl.m4 serial 4
+# ioctl.m4 serial 5
 dnl Copyright (C) 2008-2017 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -23,7 +23,10 @@ AC_DEFUN([gl_FUNC_IOCTL],
       [gl_cv_func_ioctl_posix_signature],
       [AC_COMPILE_IFELSE(
          [AC_LANG_PROGRAM(
-            [[#include <sys/ioctl.h>]],
+            [[#include <sys/ioctl.h>
+              /* On some platforms, ioctl() is declared in <unistd.h>.  */
+              #include <unistd.h>
+            ]],
             [[extern
               #ifdef __cplusplus
               "C"
diff --git a/doc/glibc-headers/sys_ioctl.texi b/doc/glibc-headers/sys_ioctl.texi
index a4cb740..5685b89 100644
--- a/doc/glibc-headers/sys_ioctl.texi
+++ b/doc/glibc-headers/sys_ioctl.texi
@@ -25,7 +25,7 @@ This header file is missing on some platforms:
 mingw, MSVC 14.
 @item
 This header file does not declare the @code{ioctl} function on some platforms:
-AIX 5.1, Solaris 11.3.
+AIX 5.1, Solaris 11.3, Haiku 2017.
 @end itemize
 
 Portability problems not fixed by Gnulib:
diff --git a/doc/posix-functions/ioctl.texi b/doc/posix-functions/ioctl.texi
index e4a1dde..b146c0a 100644
--- a/doc/posix-functions/ioctl.texi
+++ b/doc/posix-functions/ioctl.texi
@@ -15,7 +15,7 @@ On Windows platforms (excluding Cygwin), @code{ioctl} is 
called
 @item
 The second parameter is of type @code{unsigned long} rather than @code{int}
 on some platforms:
-glibc 2.26, Mac OS X 10.5, FreeBSD 11.0, NetBSD 7.0, OpenBSD 6.0, BeOS.
+glibc 2.26, Mac OS X 10.5, FreeBSD 11.0, NetBSD 7.0, OpenBSD 6.0, BeOS, Haiku 
2017.
 @end itemize
 
 Portability problems not fixed by Gnulib:
diff --git a/lib/sys_ioctl.in.h b/lib/sys_ioctl.in.h
index 9763a6c..b4f7e7d 100644
--- a/lib/sys_ioctl.in.h
+++ b/lib/sys_ioctl.in.h
@@ -31,6 +31,7 @@
 
 /* AIX 5.1 and Solaris 10 declare ioctl() in <unistd.h> and in <stropts.h>,
    but not in <sys/ioctl.h>.
+   Haiku declares ioctl() in <unistd.h>, but not in <sys/ioctl.h>.
    But avoid namespace pollution on glibc systems.  */
 #ifndef __GLIBC__
 # include <unistd.h>