Re: AC_PROG_CC_C99 and AC_OPENMP

[Ralf Wildenhues]

Hello Joel,

* Joel J. Adamson wrote on Wed, May 05, 2010 at 09:34:55PM CEST:
> I have just tried to build one of my autotools-based projects on a
> machine with Autoconf 2.59 [1], and it does not recognize
> 
> AC_PROG_CC_C99
> AC_OPENMP

Yep.  AC_PROG_CC_C99 was added in 2.59c, and AC_OPENMP in 2.62,
according to the NEWS file.

If you don't need to work with Autoconf < 2.62, I suggest you add an
  AC_PREREQ([2.62])

to your configure.ac file.  If you do need it, then for AC_OPENMP your
best bet is grabbing the macro from gnulib, or the similar ACX_OPENMP
from the Autoconf Macro Archive, but the latter has slightly different
semantics IIRC.  I don't know whether there were alternatives for
AC_PROG_CC_C99, you might just want to use something like
  m4_ifdef([AC_PROG_CC_C99], [AC_PROG_CC_C99])

to avoid the error if it's not there, and advise your co-developers with
older Autoconfen to not build the distribution tarball, and supply a
flag for C99 mode to their $CC setting.

> /netscr/adamsonj/haploid: Wed May 05> libtoolize 
> Remember to add `AC_PROG_LIBTOOL' to `configure.ac'.[2]
> You should add the contents of `/usr/share/aclocal/libtool.m4' to 
> `aclocal.m4'.
> /netscr/adamsonj/haploid: Wed May 05> cat /usr/share/aclocal/libtool.m4 >> 
> aclocal.m4
> /netscr/adamsonj/haploid: Wed May 05> aclocal

> [2]  I remember doing this when I first wrote configure.ac and it said I
> should replace it with LT_INIT which is what I have, but then the older
> version complains; I suppose this makes sense.

Not quite.  libtoolize should be content with AC_PROG_LIBTOOL (which you
should use when portability to older Libtool is important).  However,
something like
  aclocal
  libtoolize
  aclocal
  ...

should prevent the warning; no need to actually cat libtool.m4 there.

Cheers,
Ralf