Re: [PATCH] Consistent use of AC_LANG_PROGRAM in configure.ac and aclocal.m4.

From: Jonathan Nieder <jrnieder@gmail.com>
Date: Jan 2, 2011, 07:59 UTC
Message-ID: <20110102075953.GB8937@burratino>
In-Reply-To: <20110102060044.GJ19818@gmx.de>

Ralf Wildenhues wrote:

Show 8 quoted lines

> This avoids warnings from Autoconf 2.68 about missing use of
> AC_LANG_PROGRAM and friends.
> 
> Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>
> ---
> 
> The patch should not cause any semantic changes in the generated
> configure script.

This part belongs in the commit message too, imho (though no need to resend just for that, of course).

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> --- a/configure.ac
> +++ b/configure.ac
> @@ -345,7 +345,7 @@ esac
>  AC_CACHE_CHECK([if linker supports -R], git_cv_ld_dashr, [
>     SAVE_LDFLAGS="${LDFLAGS}"
>     LDFLAGS="${SAVE_LDFLAGS} -R /"
> -   AC_LINK_IFELSE(AC_LANG_PROGRAM([], []), [git_cv_ld_dashr=yes], [git_cv_ld_dashr=no])
> +   AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])], [git_cv_ld_dashr=yes], [git_cv_ld_dashr=no])

Could you say a few words about the effect of this? Mostly because it would be useful to people down the line tempted to make the same mistake again.

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> @@ -500,7 +494,7 @@ for l in $lib_order; do
>      old_LIBS="$LIBS"
>      LIBS="$LIBS $l"
>      AC_MSG_CHECKING([for iconv in $l])
> -    AC_LINK_IFELSE(ICONVTEST_SRC,
> +    AC_LINK_IFELSE([ICONVTEST_SRC],

I'm curious about this one, too.

Show 11 quoted lines

> @@ -931,18 +915,16 @@ AC_SUBST(NO_INITGROUPS)
>  #
>  # Define PTHREAD_LIBS to the linker flag used for Pthread support.
>  AC_DEFUN([PTHREADTEST_SRC], [
> +AC_LANG_PROGRAM([[
>  #include <pthread.h>
> -
> -int main(void)
> -{
> +]], [[
>  	pthread_mutex_t test_mutex;

By the way, what problem is the warning about AC_LANG_PROGRAM meant to prevent? (Just curious. A five-minute google search didn't reveal anything obvious.)

Thanks, Jonathan