Re: Is it safe to use ax_gcc_builtin to detect __builtin_offsetof?

On Sun, 25 Feb 2024 at 07:29, Jeffrey Walton <[email protected]> wrote:
>
> Cancel. We can't use AX_GCC_BUILTIN in production. Using
> AX_GCC_BUILTIN produces broken configure's:

That's weird it didn't work. I tried with this minimal file (autoconf
2.71) and it was fine:


#                                               -*- Autoconf -*-
# Process this file with autoconf to produce a configure script.

AC_PREREQ([2.71])
AC_INIT([FULL-PACKAGE-NAME], [VERSION], [BUG-REPORT-ADDRESS])
AC_CONFIG_SRCDIR([me.c])
AC_CONFIG_HEADERS([config.h])

# Checks for programs.
AC_PROG_CC

# Checks for libraries.

# Checks for header files.

# Checks for typedefs, structures, and compiler characteristics.
AX_GCC_BUILTIN([__builtin_bswap16])
AX_GCC_BUILTIN([__builtin_offsetof])


# Checks for library functions.

AC_OUTPUT

I had to put the ax_gcc_builtin.m4 file in m4/ and run aclocal, did
you also do this?

Peter