Merge GDB 7.5.1

gdb/gnulib/m4/include_next.m4

-# include_next.m4 serial 14
-dnl Copyright (C) 2006-2011 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__'.
-
-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"
-     AC_COMPILE_IFELSE([#include <conftest.h>],
-       [gl_cv_have_include_next=yes],
-       [CPPFLAGS="$gl_save_CPPFLAGS -Iconftestd1a -Iconftestd2"
-        AC_COMPILE_IFELSE([#include <conftest.h>],
-          [gl_cv_have_include_next=buggy],
-          [gl_cv_have_include_next=no])
-       ])
-     CPPFLAGS="$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])
-])
-
-# 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.
-AC_DEFUN([gl_CHECK_NEXT_HEADERS],
-[
-  AC_REQUIRE([gl_INCLUDE_NEXT])
-  AC_REQUIRE([AC_CANONICAL_HOST])
-  AC_CHECK_HEADERS_ONCE([$1])
-
-  m4_foreach_w([gl_HEADER_NAME], [$1],
-    [AS_VAR_PUSHDEF([gl_next_header],
-                    [gl_cv_next_]m4_defn([gl_HEADER_NAME]))
-     if test $gl_cv_have_include_next = yes; then
-       AS_VAR_SET([gl_next_header], ['<'gl_HEADER_NAME'>'])
-     else
-       AC_CACHE_CHECK(
-         [absolute name of <]m4_defn([gl_HEADER_NAME])[>],
-         m4_defn([gl_next_header]),
-         [AS_VAR_PUSHDEF([gl_header_exists],
-                         [ac_cv_header_]m4_defn([gl_HEADER_NAME]))
-          if test AS_VAR_GET(gl_header_exists) = yes; then
-            AC_LANG_CONFTEST(
-              [AC_LANG_SOURCE(
-                 [[#include <]]m4_dquote(m4_defn([gl_HEADER_NAME]))[[>]]
-               )])
-            dnl AIX "xlc -E" and "cc -E" omit #line directives for header files
-            dnl that contain only a #include of other header files and no
-            dnl non-comment tokens of their own. This leads to a failure to
-            dnl detect the absolute name of <dirent.h>, <signal.h>, <poll.h>
-            dnl and others. The workaround is to force preservation of comments
-            dnl through option -C. This ensures all necessary #line directives
-            dnl are present. GCC supports option -C as well.
-            case "$host_os" in
-              aix*) gl_absname_cpp="$ac_cpp -C" ;;
-              *)    gl_absname_cpp="$ac_cpp" ;;
-            esac
-            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_next_header],
-              ['"'`(eval "$gl_absname_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD |
-               sed -n '\#/]m4_defn([gl_HEADER_NAME])[#{
-                 s#.*"\(.*/]m4_defn([gl_HEADER_NAME])[\)".*#\1#
-                 s#^/[^/]#//&#
-                 p
-                 q
-               }'`'"'])
-          else
-            AS_VAR_SET([gl_next_header], ['<'gl_HEADER_NAME'>'])
-          fi
-          AS_VAR_POPDEF([gl_header_exists])])
-     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])])
-])