configure: Add macros to check for #include_next and add a workaround.

This will be used for the #include_next in string.h in the following
commit.

Signed-off-by: Ben Pfaff <blp@nicira.com>

Makefile.am

@@ -283,6 +283,7 @@ if LINUX_ENABLED
 	cd datapath/linux && $(MAKE) modules_install
 endif
 
+include m4/automake.mk
 include lib/automake.mk
 include ofproto/automake.mk
 include utilities/automake.mk

NOTICE

@@ -2,7 +2,7 @@ This file is included in compliance with the Apache 2.0 license,
 available at http://www.apache.org/licenses/LICENSE-2.0.html
 
 Open vSwitch
-Copyright (c) 2007, 2008, 2009, 2010, 2011 Nicira, Inc.
+Copyright (c) 2007, 2008, 2009, 2010, 2011, 2013 Nicira, Inc.
 
 Open vSwitch BSD port
 Copyright (c) 2011 Gaetano Catalli
@@ -19,3 +19,6 @@ Illinois at Urbana-Champaign.
 
 lib/ovs.tmac includes troff macros written by Eric S. Raymond
 and Werner Lemberg.
+
+m4/include_next.m4 and m4/absolute-header.m4
+Copyright (C) 2006-2013 Free Software Foundation, Inc.

build-aux/.gitignore

@@ -1,4 +1,6 @@
 /compile
+/config.guess
+/config.sub
 /depcomp
 /install-sh
 /missing

debian/copyright.in

@@ -8,7 +8,7 @@ Upstream Authors (from AUTHORS):
 
 Upstream Copyright Holders:
 
-	Copyright (c) 2007, 2008, 2009, 2010, 2011, 2012 Nicira, Inc.
+	Copyright (c) 2007, 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
 	Copyright (c) 2010 Jean Tourrilhes - HP-Labs.
 	Copyright (c) 2008,2009,2010 Citrix Systems, Inc.
 	and authors listed above.
@@ -182,6 +182,14 @@ License:
     .\" Copyright (C) 2007, 2009, 2011 Free Software Foundation, Inc.
     .\" You may freely use, modify and/or distribute this file.
 
+* m4/absolute-header.m4, by Derek Price, and m4/include_next.m4, by
+  Paul Eggert and Derek Price bear the following notices:
+
+    Copyright (C) 2006-2013 Free Software Foundation, Inc.
+    This file is free software; the Free Software Foundation
+    gives unlimited permission to copy and/or distribute it,
+    with or without modifications, as long as this notice is preserved.
+
 * All other components of this package are licensed under
   The Apache License Version 2.0.
 

m4/absolute-header.m4

@@ -0,0 +1,102 @@
+# absolute-header.m4 serial 16
+dnl Copyright (C) 2006-2013 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Derek Price.
+
+# gl_ABSOLUTE_HEADER(HEADER1 HEADER2 ...)
+# ---------------------------------------
+# Find the absolute name of a header file, testing first if the header exists.
+# If the header were sys/inttypes.h, this macro would define
+# ABSOLUTE_SYS_INTTYPES_H to the '""' quoted absolute name of sys/inttypes.h
+# in config.h
+# (e.g. '#define ABSOLUTE_SYS_INTTYPES_H "///usr/include/sys/inttypes.h"').
+# The three "///" are to pacify Sun C 5.8, which otherwise would say
+# "warning: #include of /usr/include/... may be non-portable".
+# Use '""', not '<>', so that the /// cannot be confused with a C99 comment.
+# Note: This macro assumes that the header file is not empty after
+# preprocessing, i.e. it does not only define preprocessor macros but also
+# provides some type/enum definitions or function/variable declarations.
+AC_DEFUN([gl_ABSOLUTE_HEADER],
+[AC_REQUIRE([AC_CANONICAL_HOST])
+AC_LANG_PREPROC_REQUIRE()dnl
+dnl FIXME: gl_absolute_header and ac_header_exists must be used unquoted
+dnl until we can assume autoconf 2.64 or newer.
+m4_foreach_w([gl_HEADER_NAME], [$1],
+  [AS_VAR_PUSHDEF([gl_absolute_header],
+                  [gl_cv_absolute_]m4_defn([gl_HEADER_NAME]))dnl
+  AC_CACHE_CHECK([absolute name of <]m4_defn([gl_HEADER_NAME])[>],
+    m4_defn([gl_absolute_header]),
+    [AS_VAR_PUSHDEF([ac_header_exists],
+                    [ac_cv_header_]m4_defn([gl_HEADER_NAME]))dnl
+    AC_CHECK_HEADERS_ONCE(m4_defn([gl_HEADER_NAME]))dnl
+    if test AS_VAR_GET(ac_header_exists) = yes; then
+      gl_ABSOLUTE_HEADER_ONE(m4_defn([gl_HEADER_NAME]))
+    fi
+    AS_VAR_POPDEF([ac_header_exists])dnl
+    ])dnl
+  AC_DEFINE_UNQUOTED(AS_TR_CPP([ABSOLUTE_]m4_defn([gl_HEADER_NAME])),
+                     ["AS_VAR_GET(gl_absolute_header)"],
+                     [Define this to an absolute name of <]m4_defn([gl_HEADER_NAME])[>.])
+  AS_VAR_POPDEF([gl_absolute_header])dnl
+])dnl
+])# gl_ABSOLUTE_HEADER
+
+# gl_ABSOLUTE_HEADER_ONE(HEADER)
+# ------------------------------
+# Like gl_ABSOLUTE_HEADER, except that:
+#   - it assumes that the header exists,
+#   - it uses the current CPPFLAGS,
+#   - it does not cache the result,
+#   - it is silent.
+AC_DEFUN([gl_ABSOLUTE_HEADER_ONE],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_LANG_CONFTEST([AC_LANG_SOURCE([[#include <]]m4_dquote([$1])[[>]])])
+  dnl AIX "xlc -E" and "cc -E" omit #line directives for header files
+  dnl that contain only a #include of other header files and no
+  dnl non-comment tokens of their own. This leads to a failure to
+  dnl detect the absolute name of <dirent.h>, <signal.h>, <poll.h>
+  dnl and others. The workaround is to force preservation of comments
+  dnl through option -C. This ensures all necessary #line directives
+  dnl are present. GCC supports option -C as well.
+  case "$host_os" in
+    aix*) gl_absname_cpp="$ac_cpp -C" ;;
+    *)    gl_absname_cpp="$ac_cpp" ;;
+  esac
+changequote(,)
+  case "$host_os" in
+    mingw*)
+      dnl For the sake of native Windows compilers (excluding gcc),
+      dnl treat backslash as a directory separator, like /.
+      dnl Actually, these compilers use a double-backslash as
+      dnl directory separator, inside the
+      dnl   # line "filename"
+      dnl directives.
+      gl_dirsep_regex='[/\\]'
+      ;;
+    *)
+      gl_dirsep_regex='\/'
+      ;;
+  esac
+  dnl A sed expression that turns a string into a basic regular
+  dnl expression, for use within "/.../".
+  gl_make_literal_regex_sed='s,[]$^\\.*/[],\\&,g'
+  gl_header_literal_regex=`echo '$1' \
+                           | sed -e "$gl_make_literal_regex_sed"`
+  gl_absolute_header_sed="/${gl_dirsep_regex}${gl_header_literal_regex}/"'{
+      s/.*"\(.*'"${gl_dirsep_regex}${gl_header_literal_regex}"'\)".*/\1/
+      s|^/[^/]|//&|
+      p
+      q
+    }'
+changequote([,])
+  dnl eval is necessary to expand gl_absname_cpp.
+  dnl Ultrix and Pyramid sh refuse to redirect output of eval,
+  dnl so use subshell.
+  AS_VAR_SET([gl_cv_absolute_]AS_TR_SH([[$1]]),
+[`(eval "$gl_absname_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD |
+  sed -n "$gl_absolute_header_sed"`])
+])

m4/automake.mk

@@ -0,0 +1,10 @@
+# Copyright (C) 2013 Nicira, Inc.
+#
+# Copying and distribution of this file, with or without modification,
+# are permitted in any medium without royalty provided the copyright
+# notice and this notice are preserved.  This file is offered as-is,
+# without warranty of any kind.
+
+EXTRA_DIST += \
+	m4/absolute-header.m4 \
+	m4/include_next.m4

m4/include_next.m4

@@ -0,0 +1,223 @@
+# include_next.m4 serial 23
+dnl Copyright (C) 2006-2013 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Paul Eggert and Derek Price.
+
+dnl Sets INCLUDE_NEXT and PRAGMA_SYSTEM_HEADER.
+dnl
+dnl INCLUDE_NEXT expands to 'include_next' if the compiler supports it, or to
+dnl 'include' otherwise.
+dnl
+dnl INCLUDE_NEXT_AS_FIRST_DIRECTIVE expands to 'include_next' if the compiler
+dnl supports it in the special case that it is the first include directive in
+dnl the given file, or to 'include' otherwise.
+dnl
+dnl PRAGMA_SYSTEM_HEADER can be used in files that contain #include_next,
+dnl so as to avoid GCC warnings when the gcc option -pedantic is used.
+dnl '#pragma GCC system_header' has the same effect as if the file was found
+dnl through the include search path specified with '-isystem' options (as
+dnl opposed to the search path specified with '-I' options). Namely, gcc
+dnl does not warn about some things, and on some systems (Solaris and Interix)
+dnl __STDC__ evaluates to 0 instead of to 1. The latter is an undesired side
+dnl effect; we are therefore careful to use 'defined __STDC__' or '1' instead
+dnl of plain '__STDC__'.
+dnl
+dnl PRAGMA_COLUMNS can be used in files that override system header files, so
+dnl as to avoid compilation errors on HP NonStop systems when the gnulib file
+dnl is included by a system header file that does a "#pragma COLUMNS 80" (which
+dnl has the effect of truncating the lines of that file and all files that it
+dnl includes to 80 columns) and the gnulib file has lines longer than 80
+dnl columns.
+
+AC_DEFUN([gl_INCLUDE_NEXT],
+[
+  AC_LANG_PREPROC_REQUIRE()
+  AC_CACHE_CHECK([whether the preprocessor supports include_next],
+    [gl_cv_have_include_next],
+    [rm -rf conftestd1a conftestd1b conftestd2
+     mkdir conftestd1a conftestd1b conftestd2
+     dnl IBM C 9.0, 10.1 (original versions, prior to the 2009-01 updates) on
+     dnl AIX 6.1 support include_next when used as first preprocessor directive
+     dnl in a file, but not when preceded by another include directive. Check
+     dnl for this bug by including <stdio.h>.
+     dnl Additionally, with this same compiler, include_next is a no-op when
+     dnl used in a header file that was included by specifying its absolute
+     dnl file name. Despite these two bugs, include_next is used in the
+     dnl compiler's <math.h>. By virtue of the second bug, we need to use
+     dnl include_next as well in this case.
+     cat <<EOF > conftestd1a/conftest.h
+#define DEFINED_IN_CONFTESTD1
+#include_next <conftest.h>
+#ifdef DEFINED_IN_CONFTESTD2
+int foo;
+#else
+#error "include_next doesn't work"
+#endif
+EOF
+     cat <<EOF > conftestd1b/conftest.h
+#define DEFINED_IN_CONFTESTD1
+#include <stdio.h>
+#include_next <conftest.h>
+#ifdef DEFINED_IN_CONFTESTD2
+int foo;
+#else
+#error "include_next doesn't work"
+#endif
+EOF
+     cat <<EOF > conftestd2/conftest.h
+#ifndef DEFINED_IN_CONFTESTD1
+#error "include_next test doesn't work"
+#endif
+#define DEFINED_IN_CONFTESTD2
+EOF
+     gl_save_CPPFLAGS="$CPPFLAGS"
+     CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1b -Iconftestd2"
+dnl We intentionally avoid using AC_LANG_SOURCE here.
+     AC_COMPILE_IFELSE([AC_LANG_DEFINES_PROVIDED[#include <conftest.h>]],
+       [gl_cv_have_include_next=yes],
+       [CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1a -Iconftestd2"
+        AC_COMPILE_IFELSE([AC_LANG_DEFINES_PROVIDED[#include <conftest.h>]],
+          [gl_cv_have_include_next=buggy],
+          [gl_cv_have_include_next=no])
+       ])
+     CPPFLAGS="$gl_save_CPPFLAGS"
+     rm -rf conftestd1a conftestd1b conftestd2
+    ])
+  PRAGMA_SYSTEM_HEADER=
+  if test $gl_cv_have_include_next = yes; then
+    INCLUDE_NEXT=include_next
+    INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include_next
+    if test -n "$GCC"; then
+      PRAGMA_SYSTEM_HEADER='#pragma GCC system_header'
+    fi
+  else
+    if test $gl_cv_have_include_next = buggy; then
+      INCLUDE_NEXT=include
+      INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include_next
+    else
+      INCLUDE_NEXT=include
+      INCLUDE_NEXT_AS_FIRST_DIRECTIVE=include
+    fi
+  fi
+  AC_SUBST([INCLUDE_NEXT])
+  AC_SUBST([INCLUDE_NEXT_AS_FIRST_DIRECTIVE])
+  AC_SUBST([PRAGMA_SYSTEM_HEADER])
+  AC_CACHE_CHECK([whether system header files limit the line length],
+    [gl_cv_pragma_columns],
+    [dnl HP NonStop systems, which define __TANDEM, have this misfeature.
+     AC_EGREP_CPP([choke me],
+       [
+#ifdef __TANDEM
+choke me
+#endif
+       ],
+       [gl_cv_pragma_columns=yes],
+       [gl_cv_pragma_columns=no])
+    ])
+  if test $gl_cv_pragma_columns = yes; then
+    PRAGMA_COLUMNS="#pragma COLUMNS 10000"
+  else
+    PRAGMA_COLUMNS=
+  fi
+  AC_SUBST([PRAGMA_COLUMNS])
+])
+
+# gl_CHECK_NEXT_HEADERS(HEADER1 HEADER2 ...)
+# ------------------------------------------
+# For each arg foo.h, if #include_next works, define NEXT_FOO_H to be
+# '<foo.h>'; otherwise define it to be
+# '"///usr/include/foo.h"', or whatever other absolute file name is suitable.
+# Also, if #include_next works as first preprocessing directive in a file,
+# define NEXT_AS_FIRST_DIRECTIVE_FOO_H to be '<foo.h>'; otherwise define it to
+# be
+# '"///usr/include/foo.h"', or whatever other absolute file name is suitable.
+# That way, a header file with the following line:
+#       #@INCLUDE_NEXT@ @NEXT_FOO_H@
+# or
+#       #@INCLUDE_NEXT_AS_FIRST_DIRECTIVE@ @NEXT_AS_FIRST_DIRECTIVE_FOO_H@
+# behaves (after sed substitution) as if it contained
+#       #include_next <foo.h>
+# even if the compiler does not support include_next.
+# The three "///" are to pacify Sun C 5.8, which otherwise would say
+# "warning: #include of /usr/include/... may be non-portable".
+# Use '""', not '<>', so that the /// cannot be confused with a C99 comment.
+# Note: This macro assumes that the header file is not empty after
+# preprocessing, i.e. it does not only define preprocessor macros but also
+# provides some type/enum definitions or function/variable declarations.
+#
+# This macro also checks whether each header exists, by invoking
+# AC_CHECK_HEADERS_ONCE or AC_CHECK_HEADERS on each argument.
+AC_DEFUN([gl_CHECK_NEXT_HEADERS],
+[
+  gl_NEXT_HEADERS_INTERNAL([$1], [check])
+])
+
+# gl_NEXT_HEADERS(HEADER1 HEADER2 ...)
+# ------------------------------------
+# Like gl_CHECK_NEXT_HEADERS, except do not check whether the headers exist.
+# This is suitable for headers like <stddef.h> that are standardized by C89
+# and therefore can be assumed to exist.
+AC_DEFUN([gl_NEXT_HEADERS],
+[
+  gl_NEXT_HEADERS_INTERNAL([$1], [assume])
+])
+
+# The guts of gl_CHECK_NEXT_HEADERS and gl_NEXT_HEADERS.
+AC_DEFUN([gl_NEXT_HEADERS_INTERNAL],
+[
+  AC_REQUIRE([gl_INCLUDE_NEXT])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+
+  m4_if([$2], [check],
+    [AC_CHECK_HEADERS_ONCE([$1])
+    ])
+
+dnl FIXME: gl_next_header and gl_header_exists must be used unquoted
+dnl until we can assume autoconf 2.64 or newer.
+  m4_foreach_w([gl_HEADER_NAME], [$1],
+    [AS_VAR_PUSHDEF([gl_next_header],
+                    [gl_cv_next_]m4_defn([gl_HEADER_NAME]))
+     if test $gl_cv_have_include_next = yes; then
+       AS_VAR_SET(gl_next_header, ['<'gl_HEADER_NAME'>'])
+     else
+       AC_CACHE_CHECK(
+         [absolute name of <]m4_defn([gl_HEADER_NAME])[>],
+         m4_defn([gl_next_header]),
+         [m4_if([$2], [check],
+            [AS_VAR_PUSHDEF([gl_header_exists],
+                            [ac_cv_header_]m4_defn([gl_HEADER_NAME]))
+             if test AS_VAR_GET(gl_header_exists) = yes; then
+             AS_VAR_POPDEF([gl_header_exists])
+            ])
+           gl_ABSOLUTE_HEADER_ONE(gl_HEADER_NAME)
+           AS_VAR_COPY([gl_header], [gl_cv_absolute_]AS_TR_SH(gl_HEADER_NAME))
+           AS_VAR_SET(gl_next_header, ['"'$gl_header'"'])
+          m4_if([$2], [check],
+            [else
+               AS_VAR_SET(gl_next_header, ['<'gl_HEADER_NAME'>'])
+             fi
+            ])
+         ])
+     fi
+     AC_SUBST(
+       AS_TR_CPP([NEXT_]m4_defn([gl_HEADER_NAME])),
+       [AS_VAR_GET(gl_next_header)])
+     if test $gl_cv_have_include_next = yes || test $gl_cv_have_include_next = buggy; then
+       # INCLUDE_NEXT_AS_FIRST_DIRECTIVE='include_next'
+       gl_next_as_first_directive='<'gl_HEADER_NAME'>'
+     else
+       # INCLUDE_NEXT_AS_FIRST_DIRECTIVE='include'
+       gl_next_as_first_directive=AS_VAR_GET(gl_next_header)
+     fi
+     AC_SUBST(
+       AS_TR_CPP([NEXT_AS_FIRST_DIRECTIVE_]m4_defn([gl_HEADER_NAME])),
+       [$gl_next_as_first_directive])
+     AS_VAR_POPDEF([gl_next_header])])
+])
+
+# Autoconf 2.68 added warnings for our use of AC_COMPILE_IFELSE;
+# this fallback is safe for all earlier autoconf versions.
+m4_define_default([AC_LANG_DEFINES_PROVIDED])

m4/openvswitch.m4

@@ -458,3 +458,8 @@ dnl OVS_CHECK_POSIX_AIO
 AC_DEFUN([OVS_CHECK_POSIX_AIO],
   [AC_SEARCH_LIBS([aio_write], [rt])
    AM_CONDITIONAL([HAVE_POSIX_AIO], [test "$ac_cv_search_aio_write" != no])])
+
+dnl OVS_CHECK_INCLUDE_NEXT
+AC_DEFUN([OVS_CHECK_INCLUDE_NEXT],
+  [AC_REQUIRE([gl_CHECK_NEXT_HEADERS])
+   gl_CHECK_NEXT_HEADERS([$1])])