Re: [PATCH] AC_PROG_CC_C11: new macro, which AC_PROG_CC_STDC now defaults to

[Jim Meyering]

Paul Eggert wrote:
> I pushed this.  I did only C11, not C++11, since I'm not a
> C++ guru.
>
> * NEWS:
> * doc/autoconf.texi (C Compiler): Document this.
> (Gnulib, Function Portability, Particular Functions)
> (Header Portability, Particular Headers, Defining Symbols)
> (Printing Messages, Limitations of Usual Tools)
> (Preprocessor Arithmetic, Volatile Objects, Exiting Portably):
> Modernize wording for C11.
> * lib/autoconf/c.m4 (_AC_C_C99_TEST_HEADER, _AC_C_C99_TEST_BODY):
> New macros, taken from _AC_PROG_CC_C99.  These are so that we can
> also include the C99 tests in the C11 test program.
> (_AC_PROG_CC_C99): Use them.
> (_AC_PROG_CC_C11, AC_PROG_CC_C11): New macros.
> (AC_PROG_CC_STDC): Prefer C11 to C99 or C89.

Hi Paul,

That patch makes bootstrap/autoreconf fail for many projects.
Here's what happens with diffutils:

  running: AUTOPOINT=true LIBTOOLIZE=true  autoreconf --verbose --install 
--no-recursive -I m4
  autoreconf: Entering directory `.'
  autoreconf: running: true
  autoreconf: running: aclocal -I m4 -I m4
  configure.ac:38: error: AC_PROG_CC cannot be called after AM_PROG_CC_C_O
  ../../lib/autoconf/c.m4:1476: AC_PROG_CC_STDC is expanded from...
  m4/gnulib-common.m4:229: gl_PROG_CC_C99 is expanded from...
  m4/gnulib-comp.m4:34: gl_EARLY is expanded from...
  configure.ac:38: the top level
  autom4te: /usr/bin/m4 failed with exit status: 1
  aclocal: error: /p/bin/autom4te failed with exit status: 1
  autoreconf: aclocal failed with exit status: 1
  ./bootstrap: autoreconf failed

If I back out that change and rebuild/install autoconf,
then bootstrapping diffutils succeeds.