avoiding obsolete macros like AC_TRY_RUN [Re: gnulib-izing sharutils

[Jim Meyering]

Ralf Wildenhues wrote:
> * Bruno Haible wrote on Sun, Aug 30, 2009 at 11:30:53PM CEST:
>> > configure.ac:21: warning: The macro `AC_TRY_RUN' is obsolete.
>>
>> You can ignore these warnings. AC_TRY_RUN and AC_TRY_LINK cannot go away
>> because hundreds of autoconf macros use them.
>
> I'd venture to guess that if gnulib had heeded this warning when it was
> introduced, then by today, AC_TRY_RUN could have gone away; well, at
> least, it would not be necessary any more to remember and explain in
> detail the quoting differences of the AC_TRY_* macros over their more
> modern counterparts.  I think we all find M4 quoting rules complex
> enough already.
>
> First ignoring the warning, then complaining about its existence is
> not an excuse.  If you prefer so, we could also make the warning
> unconditionally, rather than only with -Wobsolete.  autoupdate exists
> to help with updating (and I would send patches if they had a chance of
> being applied).

Hi Ralf,

I'd welcome patches to modernize the m4/*.m4 files under my care.
Since I tend to use gnulib's files as models, it's worthwhile to
update them to use macros that aren't listed as "obsolete".

Here are some of the affected uses:

  $ grep -li meyering modules/*|xargs grep -hF .m4|xargs grep AC_TRY_RUN
  m4/fsusage.m4:  [AC_TRY_RUN([
  m4/fsusage.m4:  [AC_TRY_RUN([
  m4/fsusage.m4:  [AC_TRY_RUN([#include <sys/types.h>
  m4/fsusage.m4:  [AC_TRY_RUN([#include <sys/types.h>
  m4/fsusage.m4:  [AC_TRY_RUN([#include <sys/types.h>
  m4/link-follow.m4:    AC_TRY_RUN(
  m4/mkdir-slash.m4:      AC_TRY_RUN([
  m4/rename.m4:    AC_TRY_RUN([
  m4/rename-dest-slash.m4:    AC_TRY_RUN([
  m4/rmdir-errno.m4:      AC_TRY_RUN([
  m4/utimes-null.m4:AC_TRY_RUN([