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| author | Eric Blake <eblake@redhat.com> | 2016-12-21 08:32:29 -0600 |
|---|---|---|
| committer | Eric Blake <eblake@redhat.com> | 2016-12-21 08:32:29 -0600 |
| commit | 501ccbbfdb43561537f377a2ac66cf89f975b1b1 (patch) | |
| tree | 41e906b3614875b33ec63d0b1952551dae0be09f | |
| parent | 4523f7c32b052e805c4081fa6a55c7414d94d791 (diff) | |
| download | autoconf-501ccbbfdb43561537f377a2ac66cf89f975b1b1.tar.gz | |
AC_CHECK_HEADERS_ONCE: honor current AC_LANG
Previously, AC_CHECK_HEADERS_ONCE collected a list of header names
to check, but ran the checks using the AC_LANG that was active
during the first encounter of the macro. In practice, this is
usually the C language, and we haven't had actual reports of projects
attempting to use AC_CHECK_HEADERS_ONCE across multiple languages,
rather this was discovered by code inspection.
With this patch, the code now tracks a separate per-language list of
names to check. Note, however, that it is only possible to check for
a given header name in one language; attempting to add a name again
under AC_CHECK_HEADERS_ONCE while a different language is active is a
no-op (this still makes sense because the side-effect of defining
the CPP macro HAVE_HEADER does not include a language prefix).
* lib/autoconf/headers.m4 (_AC_CHECK_HEADER_ONCE)
(_AC_HEADERS_EXPANSION):
* NEWS: Mention it.
Signed-off-by: Eric Blake <eblake@redhat.com>
| -rw-r--r-- | NEWS | 6 | ||||
| -rw-r--r-- | lib/autoconf/headers.m4 | 19 |
2 files changed, 14 insertions, 11 deletions
@@ -111,9 +111,9 @@ GNU Autoconf NEWS - User visible changes. useful effect is to trigger those checks, with this macro. It is unlikely to be useful otherwise. -- The AC_CHECK_FUNCS_ONCE macro now supports use with multiple - languages, rather than forcing all checks in the language used by - the first encounter of the macro. +- The AC_CHECK_FUNCS_ONCE and AC_CHECK_HEADERS_ONCE macros now support + use with multiple languages, rather than forcing all checks in the + language used by the first encounter of the macro. ** Man pages for config.guess and config.sub are no longer provided. They were moved to the master source tree for config.guess and config.sub. diff --git a/lib/autoconf/headers.m4 b/lib/autoconf/headers.m4 index 72262c1e..f6264df2 100644 --- a/lib/autoconf/headers.m4 +++ b/lib/autoconf/headers.m4 @@ -194,10 +194,10 @@ AC_DEFUN([AC_CHECK_HEADERS], # Check for a single HEADER-FILE once. m4_define([_AC_CHECK_HEADER_ONCE], [_AH_CHECK_HEADER([$1])AC_DEFUN([_AC_Header_]m4_translit([[$1]], - [./-], [___]), - [m4_divert_text([INIT_PREPARE], [AS_VAR_APPEND([ac_header_list], [" $1"])]) -_AC_HEADERS_EXPANSION])AC_REQUIRE([_AC_Header_]m4_translit([[$1]], - [./-], [___]))]) + [./-], [___]), [m4_divert_text([INIT_PREPARE], + [AS_VAR_APPEND([ac_header_]]_AC_LANG_ABBREV[[_list], [" $1"])]) +_AC_HEADERS_EXPANSION(_AC_LANG_ABBREV)])AC_REQUIRE( + [_AC_Header_]m4_translit([[$1]], [./-], [___]))]) # AC_CHECK_HEADERS_ONCE(HEADER-FILE...) @@ -213,11 +213,14 @@ AC_DEFUN([AC_CHECK_HEADERS_ONCE], AC_DEFUN([_AC_CHECK_HEADERS_ONCE], [m4_map_args_w([$1], [_AC_CHECK_HEADER_ONCE(], [)])]) +# _AC_HEADERS_EXPANSION(LANG) +# --------------------------- +# One-shot code per language LANG for checking all headers registered by +# AC_CHECK_HEADERS_ONCE while that language was active. m4_define([_AC_HEADERS_EXPANSION], - [m4_divert_text([DEFAULTS], [ac_header_list=])]dnl - [AC_CHECK_HEADERS([$ac_header_list], [], [], [$ac_includes_default])]dnl - [m4_define([_AC_HEADERS_EXPANSION], [])]) - +[m4_ifndef([$0($1)], [m4_define([$0($1)])m4_divert_text([DEFAULTS], +[ac_header_$1_list=])AC_CHECK_HEADERS([$ac_header_$1_list], [], [], + [$ac_includes_default])])]) |