Re: Make fnstcw work with emscripten

[Diomidis Spinellis]

Hi Bruno,

On 13-Oct-19 3:21, Bruno Haible wrote:
> > When glibc is compiled with emscripten toolchain for compiling to asm.js
> > and WebAssembly [1] (e.g. as part of groff),
>
> You mean gnulib, not glibc? glibc is not built when you compile groff.

Yes, I meant gnulib.

> > the compilation fails due
> > to the inclusion of assembly code, as shown in the example below.
[...]
> When you run
>    $ touch empty.c; emcc -E -dM empty.c |grep '\(i386\|x86_64\)'
> does is display such macro definitions?
>
> If yes, your emcc compiler is misconfigured. For me, it does not
> define __i386__ or __x86_64__; it defines __asmjs__ instead.

Indeed I verified that emcc on its own defines __asmjs__, not __i386__ 
or __x86_64__.

> If not, it means that some file defines __i386__ or __x86_64__
> during the compilation. But application files should not do this.
> In this case, your groff.bc (or one of the files that it includesE
> directly or indirectly) is buggy.

By running gcc on lib/vasnprintf.c with the same flags as emcc (as shown 
with emmake make V=1) plus -E -fdirectives-only I found that groff's 
src/include/config.h defines __i386__.

#ifndef __i386__
#define __i386__ 1
#endif

Removing the definition fixes the problem.  So it's a bug of emconfigure 
or groff's autoconf.

Many thanks,

Diomidis