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      1 # absolute-header.m4 serial 6
      2 dnl Copyright (C) 2006 Free Software Foundation, Inc.
      3 dnl This file is free software; the Free Software Foundation
      4 dnl gives unlimited permission to copy and/or distribute it,
      5 dnl with or without modifications, as long as this notice is preserved.
      6 
      7 dnl From Derek Price.
      8 
      9 # gl_ABSOLUTE_HEADER(HEADER1 HEADER2 ...)
     10 # ---------------------------------------
     11 # Find the absolute name of a header file, assuming the header exists.
     12 # If the header were sys/inttypes.h, this macro would define
     13 # ABSOLUTE_SYS_INTTYPES_H to the `""' quoted absolute name of sys/inttypes.h
     14 # in config.h
     15 # (e.g. `#define ABSOLUTE_SYS_INTTYPES_H "///usr/include/sys/inttypes.h"').
     16 # The three "///" are to pacify Sun C 5.8, which otherwise would say
     17 # "warning: #include of /usr/include/... may be non-portable".
     18 # Use `""', not `<>', so that the /// cannot be confused with a C99 comment.
     19 AC_DEFUN([gl_ABSOLUTE_HEADER],
     20 [AC_LANG_PREPROC_REQUIRE()dnl
     21 AC_FOREACH([gl_HEADER_NAME], [$1],
     22   [AS_VAR_PUSHDEF([gl_absolute_header],
     23                   [gl_cv_absolute_]m4_quote(m4_defn([gl_HEADER_NAME])))dnl
     24   AC_CACHE_CHECK([absolute name of <]m4_quote(m4_defn([gl_HEADER_NAME]))[>],
     25     m4_quote(m4_defn([gl_absolute_header])),
     26     [AS_VAR_PUSHDEF([ac_header_exists],
     27                     [ac_cv_header_]m4_quote(m4_defn([gl_HEADER_NAME])))dnl
     28     AC_CHECK_HEADERS_ONCE(m4_quote(m4_defn([gl_HEADER_NAME])))dnl
     29     if test AS_VAR_GET(ac_header_exists) = yes; then
     30       AC_LANG_CONFTEST([AC_LANG_SOURCE([[#include <]]m4_dquote(m4_defn([gl_HEADER_NAME]))[[>]])])
     31 dnl eval is necessary to expand ac_cpp.
     32 dnl Ultrix and Pyramid sh refuse to redirect output of eval, so use subshell.
     33       AS_VAR_SET(gl_absolute_header,
     34 [`(eval "$ac_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD |
     35 sed -n '\#/]m4_quote(m4_defn([gl_HEADER_NAME]))[#{s#.*"\(.*/]m4_quote(m4_defn([gl_HEADER_NAME]))[\)".*#\1#;s#^/[^/]#//&#;p;q;}'`])
     36     fi
     37     AS_VAR_POPDEF([ac_header_exists])dnl
     38     ])dnl
     39   AC_DEFINE_UNQUOTED(AS_TR_CPP([ABSOLUTE_]m4_quote(m4_defn([gl_HEADER_NAME]))),
     40                      ["AS_VAR_GET(gl_absolute_header)"],
     41                      [Define this to an absolute name of <]m4_quote(m4_defn([gl_HEADER_NAME]))[>.])
     42   AS_VAR_POPDEF([gl_absolute_header])dnl
     43 ])dnl
     44 ])# gl_ABSOLUTE_HEADER
     45