Re: confdefs.h not being included by AC_LANG_SOURCE()

[Ralf Wildenhues]

* Brian J. Murrell wrote on Mon, Mar 01, 2010 at 11:03:26PM CET:
> AC_INIT([pkg], [1.0])
> 
> #
> # LB_LINUX_COMPILE_IFELSE
> #
> # like AC_COMPILE_IFELSE
> #
> AC_DEFUN([LB_LINUX_COMPILE_IFELSE],
> [m4_ifvaln([$1], [LB_LINUX_CONFTEST([$1])])dnl
> rm -f build/conftest.o build/conftest.mod.c build/conftest.ko
> AS_IF([AC_TRY_COMMAND(cp conftest.c build && make -d [$2] ${LD:+"LD=$LD"} 
> CC="$CC" -f $PWD/build/Makefile LUSTRE_LINUX_CONFIG=$LINUX_CONFIG 
> LINUXINCLUDE="$EXTRA_LNET_INCLUDE -I$LINUX/arch/`uname -m|sed -e 
> 's/ppc.*/powerpc/' -e 's/x86_64/x86/' -e 's/i.86/x86/'`/include 
> -I$LINUX/include -I$LINUX_OBJ/include -I$LINUX_OBJ/include2 -include 
> include/linux/autoconf.h" -o tmp_include_depends -o scripts -o 
> include/config/MARKER -C $LINUX_OBJ 
> EXTRA_CFLAGS="-Werror-implicit-function-declaration $EXTRA_KCFLAGS" $ARCH_UM 
> $MODULE_TARGET=$PWD/build) >/dev/null && AC_TRY_COMMAND([$3])],
>       [$4],
>       [_AC_MSG_LOG_CONFTEST
> m4_ifvaln([$5],[$5])dnl])
> rm -f build/conftest.o build/conftest.mod.c build/conftest.mod.o 
> build/conftest.ko m4_ifval([$1], [build/conftest.c conftest.c])[]dnl
> ])
> 
> LB_LINUX_COMPILE_IFELSE([AC_LANG_SOURCE([[#include <linux/thread_info.h>
>         #if THREAD_SIZE < 8192
>         #error "stack size < 8192"
>         #endif
> ]],[],[echo foo])])
> ---------
> 
> As you can see it's similar to your test case but when I try to autoconf
> it I get:
> 
> $ autoconf
> configure.ac:18: error: possibly undefined macro: AC_LANG_SOURCE

You also need a definition of LB_LINUX_CONFTEST, since you use it in
LB_LINUX_COMPILE_IFELSE.  autoconf expands the $1 argument in that
undefined macro to the string AC_LANG_SOURCE and complains, because,
without LB_LINUX_CONFTEST being a macro, its argument is sufficiently
quoted to not undergo m4 expansion.

Cheers,
Ralf