Re: Building Emacs-trunk with gcc >= 4.5.1 and libelf installed

[Angelo Graziosi <angelo.graziosi@alice.it>]

Yaakov ,
thanks for clarifications and suggestions. I hope someone on the Emacs 
list can recipie and apply them appropriately.

Emacs guys,
the simplest workaround I found to fix the issue was to add

#undef SVR4

in src/s/cygwin.h

Thanks,
Angelo.


Yaakov (Cygwin/X) wrote:
> On Tue, 2010-08-24 at 01:31 +0200, Angelo Graziosi wrote:
>> Trying to build Emacs-trunk on Cygwin with GCC >= 4.5.1, I have found a
>> problem if also the package 'libelf0' is installed.
> [snip]
>> and the following test in 'configure' script is true:
> [snip]
>> i.e. SVR4 is _defined_. But... 'src/xfaces.c' includes indirectly via
>> '/usr/include/X11/Xos.h' the header '/usr/include/X11/Xarch.h', which has:
> [snip]
>> i.e. finding SVR4 defined, it searches for 'byteorder.h' in
>> '/usr/include/sys' and not in '/usr/include/asm', where it lives (*as on
>> GNU/Linux*[1]), and this leads to the above failure.
>
> This is coming from autoconf's AC_FUNC_GETLOADAVG, which tries to find
> several different getloadavg(3) implementations (which Cygwin doesn't
> provide), otherwise it points to an AC_LIBOBJ from gnulib.  On Solaris,
> the gnulib getloadavg uses kvm_open(3) and friends, and libkvm requires
> libelf, hence the check for the latter.
>
> AFAICS the proper solution is, in _AC_LIBOBJ_GETLOADAVG:
>
> if test $ac_have_func = no && test "$ac_cv_lib_elf_elf_begin" = yes;
> then
>   ac_have_func=yes
>   AC_DEFINE(SVR4, 1, [Define to 1 on System V Release 4.])
> fi
>
> to add << && test "$ac_cv_lib_kvm_kvm_open" = yes >> to the conditional.
>
> In the meantime, since libelf isn't needed elsewhere in emacs, an easy
> workaround is to add "ac_cv_lib_elf_elf_begin=no" to CYGCONF_ARGS.