Sylvain Beucler wrote: > it seems alloca.h is not yet present at ./configure time > (there's only gnulib/lib/alloca.in.h). So AC_CHECK_HEADERS fails > anyway: > > configure:14417: checking SDL.h usability > configure:14434: i586-mingw32msvc-gcc -c -g -O2 > -I/usr/local/cross-tools/i386-mingw32/include/SDL -D_GNU_SOURCE=1 > -Dmain=SDL_main > -I/usr/local/cross-tools/i386-mingw32/include/SDL -D_GNU_SOURCE=1 > -Dmain=SDL_main > -I../gnulib/lib -I./gnulib/lib conftest.c >&5 > In file included from > /usr/local/cross-tools/i386-mingw32/include/SDL/SDL_main.h:26, > from > /usr/local/cross-tools/i386-mingw32/include/SDL/SDL.h:28, > from conftest.c:117: > /usr/local/cross-tools/i386-mingw32/include/SDL/SDL_stdinc.h:169:22: error: > alloca.h: No such > file or directory
This should be fixable by using AH_VERBATIM instead of AC_DEFINE to define HAVE_ALLOCA_H. As I understand it, AC_DEFINE makes the macro available immediately, at configure time, whereas AH_VERBATIM makes it available only after configuration, when config.h is created. See patch below (untested). Paul Eggert wrote: > Well, it _has_ been 3 years. If the backward-compatibility gorp is > causing real problems, perhaps it's time to bite the bullet and drop > it, something like the following. This won't affect coreutils or > diffutils or tar or any modernish program. What would it hurt? The problems mentioned in the 2004 thread http://lists.gnu.org/archive/html/bug-gnulib/2004-04/threads.html#00021 have not gone away. - The autoconf manual still recommends to include <alloca.h> only if HAVE_ALLOCA_H. - fnmatch.c and regex.c are still included in gcc's libiberty. Its regex.c also includes <alloca.h> only if HAVE_ALLOCA_H. So, if AH_VERBATIM solves Sylvain's problem, I would prefer to not disturb all the sources which follow the advice in the autoconf manual. Paul, what do you think? Bruno *** m4/alloca.m4.orig --- m4/alloca.m4 *************** *** 1,4 **** ! # alloca.m4 serial 7 dnl Copyright (C) 2002-2004, 2006 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, --- 1,4 ---- ! # alloca.m4 serial 8 dnl Copyright (C) 2002-2004, 2006 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, *************** *** 40,48 **** fi AC_SUBST([ALLOCA_H]) ! AC_DEFINE(HAVE_ALLOCA_H, 1, ! [Define HAVE_ALLOCA_H for backward compatibility with older code ! that includes <alloca.h> only if HAVE_ALLOCA_H is defined.]) ]) # Prerequisites of lib/alloca.c. --- 40,55 ---- fi AC_SUBST([ALLOCA_H]) ! dnl Use AH_VERBATIM here, not AC_DEFINE, so that the HAVE_ALLOCA_H ! dnl is still undefined at configuration time. This is needed for ! dnl AC_CHECK_HEADER tests that look for include files that use the idiom: ! dnl #if HAVE_ALLOCA_H ! dnl # include <alloca.h> ! dbl #endif ! AH_VERBATIM([gl_FUNC_ALLOCA], [ ! /* Define HAVE_ALLOCA_H for backward compatibility with older code ! that includes <alloca.h> only if HAVE_ALLOCA_H is defined. */ ! #define HAVE_ALLOCA_H 1]) ]) # Prerequisites of lib/alloca.c.
