- [absolute name of <]m4_quote(m4_defn([gl_HEADER_NAME]))[>],
- m4_quote(m4_defn([gl_next_header])),
- [AS_VAR_PUSHDEF([gl_header_exists],
- [ac_cv_header_]m4_quote(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 eval is necessary to expand ac_cpp.
- dnl Ultrix and Pyramid sh refuse to redirect output of eval,
- dnl so use subshell.
- AS_VAR_SET([gl_next_header],
- ['"'`(eval "$ac_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD |
- sed -n '\#/]m4_quote(m4_defn([gl_HEADER_NAME]))[#{
- s#.*"\(.*/]m4_quote(m4_defn([gl_HEADER_NAME]))[\)".*#\1#
- s#^/[^/]#//&#
- p
- q
- }'`'"'])
- else
- AS_VAR_SET([gl_next_header], ['<'gl_HEADER_NAME'>'])
- fi
- AS_VAR_POPDEF([gl_header_exists])])
+ [absolute name of <]m4_defn([gl_HEADER_NAME])[>],
+ m4_defn([gl_next_header]),
+ [m4_if([$2], [check],
+ [AS_VAR_PUSHDEF([gl_header_exists],
+ [ac_cv_header_]m4_defn([gl_HEADER_NAME]))
+ if test AS_VAR_GET(gl_header_exists) = yes; then
+ AS_VAR_POPDEF([gl_header_exists])
+ ])
+ AC_LANG_CONFTEST(
+ [AC_LANG_SOURCE(
+ [[#include <]]m4_dquote(m4_defn([gl_HEADER_NAME]))[[>]]
+ )])
+ dnl AIX "xlc -E" and "cc -E" omit #line directives for header
+ dnl files that contain only a #include of other header files and
+ dnl no non-comment tokens of their own. This leads to a failure
+ dnl to detect the absolute name of <dirent.h>, <signal.h>,
+ dnl <poll.h> and others. The workaround is to force preservation
+ dnl of comments through option -C. This ensures all necessary
+ dnl #line directives are present. GCC supports option -C as well.
+ case "$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
+ }'`'"'])
+ m4_if([$2], [check],
+ [else
+ AS_VAR_SET([gl_next_header], ['<'gl_HEADER_NAME'>'])
+ fi
+ ])
+ ])