poll-h: create poll.h always

[Bruno Haible]

Eric Blake wrote:
> we need a new module poll-h if you want a working poll.h 
> [pollfd, nfds_t, and the various POLL macros] that can be used for 
> GNULIB_POSIXCHECK conformance

For using GNULIB_POSIXCHECK it is also necessary to create the .h file on
all platforms. Like what you did on 2009-12-31.


2010-09-28  Bruno Haible  <address@hidden>

        poll-h: Create poll.h on all platforms.
        * lib/poll.in.h: Use double-inclusion guard. Don't define POLL*,
        struct pollfd, nfds_t, INFTIM when the system has <poll.h>.
        * m4/poll_h.m4 (gl_POLL_H): Set HAVE_POLL_H. Invoke
        gl_CHECK_NEXT_HEADERS. Don't set POLL_H.
        (gl_REPLACE_POLL_H): Don't set POLL_H.
        (gl_POLL_H_DEFAULTS): Don't initialize POLL_H.
        * modules/poll-h (Depends-on): Add include_next.
        (Makefile.am): Create poll.h unconditionally. Substitute also
        HAVE_POLL_H, INCLUDE_NEXT, PRAGMA_SYSTEM_HEADER, NEXT_POLL_H.

--- lib/poll.in.h.orig  Wed Sep 29 01:43:50 2010
+++ lib/poll.in.h       Wed Sep 29 01:35:54 2010
@@ -20,6 +20,17 @@
    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
 
 #ifndef _GL_POLL_H
+
+#if __GNUC__ >= 3
address@hidden@
+#endif
+
+/* The include_next requires a split double-inclusion guard.  */
+#if @HAVE_POLL_H@
+# @INCLUDE_NEXT@ @NEXT_POLL_H@
+#endif
+
+#ifndef _GL_POLL_H
 #define _GL_POLL_H
 
 
@@ -28,17 +39,19 @@
 /* The definition of _GL_WARN_ON_USE is copied here.  */
 
 
+#if address@hidden@
+
 /* fake a poll(2) environment */
-#define POLLIN      0x0001      /* any readable data available   */
-#define POLLPRI     0x0002      /* OOB/Urgent readable data      */
-#define POLLOUT     0x0004      /* file descriptor is writeable  */
-#define POLLERR     0x0008      /* some poll error occurred      */
-#define POLLHUP     0x0010      /* file descriptor was "hung up" */
-#define POLLNVAL    0x0020      /* requested events "invalid"    */
-#define POLLRDNORM  0x0040
-#define POLLRDBAND  0x0080
-#define POLLWRNORM  0x0100
-#define POLLWRBAND  0x0200
+# define POLLIN      0x0001      /* any readable data available   */
+# define POLLPRI     0x0002      /* OOB/Urgent readable data      */
+# define POLLOUT     0x0004      /* file descriptor is writeable  */
+# define POLLERR     0x0008      /* some poll error occurred      */
+# define POLLHUP     0x0010      /* file descriptor was "hung up" */
+# define POLLNVAL    0x0020      /* requested events "invalid"    */
+# define POLLRDNORM  0x0040
+# define POLLRDBAND  0x0080
+# define POLLWRNORM  0x0100
+# define POLLWRBAND  0x0200
 
 struct pollfd
 {
@@ -49,6 +62,14 @@
 
 typedef unsigned long nfds_t;
 
+/* Define INFTIM only if doing so conforms to POSIX.  */
+# if !defined (_POSIX_C_SOURCE) && !defined (_XOPEN_SOURCE)
+#  define INFTIM (-1)
+# endif
+
+#endif
+
+
 #if @GNULIB_POLL@
 # if @REPLACE_POLL@
 #  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
@@ -72,10 +93,6 @@
 # endif
 #endif
 
-/* Define INFTIM only if doing so conforms to POSIX.  */
-#if !defined (_POSIX_C_SOURCE) && !defined (_XOPEN_SOURCE)
-#define INFTIM (-1)
-#endif
-
 
 #endif /* _GL_POLL_H */
+#endif /* _GL_POLL_H */
--- m4/poll_h.m4.orig   Wed Sep 29 01:43:50 2010
+++ m4/poll_h.m4        Wed Sep 29 01:40:05 2010
@@ -13,9 +13,16 @@
   AC_REQUIRE([gl_POLL_H_DEFAULTS])
 
   AC_CHECK_HEADERS_ONCE([poll.h])
-  if test $ac_cv_header_poll_h != yes; then
+  if test $ac_cv_header_poll_h = yes; then
+    HAVE_POLL_H=1
+  else
+    HAVE_POLL_H=0
     gl_REPLACE_POLL_H
   fi
+  AC_SUBST([HAVE_POLL_H])
+
+  dnl <poll.h> is always overridden, because of GNULIB_POSIXCHECK.
+  gl_CHECK_NEXT_HEADERS([poll.h])
 
   dnl Check for declarations of anything we want to poison if the
   dnl corresponding gnulib module is not in use.
@@ -26,8 +33,8 @@
 dnl Unconditionally enables the replacement of <poll.h>.
 AC_DEFUN([gl_REPLACE_POLL_H],
 [
-  AC_REQUIRE([gl_POLL_H_DEFAULTS])
-  POLL_H='poll.h'
+  dnl This is a no-op, because <poll.h> is always overridden.
+  :
 ])
 
 AC_DEFUN([gl_POLL_MODULE_INDICATOR],
@@ -43,7 +50,6 @@
 [
   GNULIB_POLL=0;        AC_SUBST([GNULIB_POLL])
   dnl Assume proper GNU behavior unless another module says otherwise.
-  POLL_H='';            AC_SUBST([POLL_H])
   HAVE_POLL=1;          AC_SUBST([HAVE_POLL])
   REPLACE_POLL=0;       AC_SUBST([REPLACE_POLL])
 ])
--- modules/poll-h.orig Wed Sep 29 01:43:50 2010
+++ modules/poll-h      Wed Sep 29 01:40:55 2010
@@ -8,20 +8,25 @@
 Depends-on:
 c++defs
 extensions
+include_next
 warn-on-use
 
 configure.ac:
 gl_POLL_H
 
 Makefile.am:
-BUILT_SOURCES += $(POLL_H)
+BUILT_SOURCES += poll.h
 
 # We need the following in order to create <poll.h> when the system
 # doesn't have one.
 poll.h: poll.in.h $(CXXDEFS_H) $(WARN_ON_USE_H)
        $(AM_V_GEN)rm -f address@hidden $@ && \
        { echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */'; \
-         sed -e 's|@''GNULIB_POLL''@|$(GNULIB_POLL)|g' \
+         sed -e 's|@''HAVE_POLL_H''@|$(HAVE_POLL_H)|g' \
+             -e 's|@''INCLUDE_NEXT''@|$(INCLUDE_NEXT)|g' \
+             -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
+             -e 's|@''NEXT_POLL_H''@|$(NEXT_POLL_H)|g' \
+             -e 's|@''GNULIB_POLL''@|$(GNULIB_POLL)|g' \
              -e 's|@''HAVE_POLL''@|$(HAVE_POLL)|g' \
              -e 's|@''REPLACE_POLL''@|$(REPLACE_POLL)|g' \
              -e '/definitions of _GL_FUNCDECL_RPL/r $(CXXDEFS_H)' \