Re: cygwin -mno-cygwin AC_CHECK_SIZEOF

[Bob Rossi <bob_rossi at cox dot net>]

On Fri, Dec 01, 2006 at 07:06:06AM -0700, Eric Blake wrote:
> According to Bob Rossi on 12/1/2006 6:57 AM:
> > CPPFLAGS="-mno-cygwin" CFLAGS="-mno-cygwin -O0" 
> > ./configure --build=mingw32 --enable-experimental-libtool 
> 
> EVIL.  --build is for the platform you are BUILDING on (ie. cygwin), NOT
> the platform you are compiling for (ie. using -mno-cygwin says you are
> cross-compiling for mingw).  By lying to configure, you are asking for
> problems.  *Don't do that.*  Also, setting environment variables prior to
> ./configure is deprecated, because rerunning ./config.status won't
> remember that you set those variables.  And since -mno-cygwin is changing
> from a regular to a cross-compiler, you really should be setting it in CC
> rather than CFLAGS, so that the change happens everywhere.
> 
> So, if you INSIST on using the cygwin environment to cross-compile mingw
> binaries, you should use:
> 
> ./configure --build=i686-pc-cygwin --host=i686-pc-mingw32 \
>   CC='gcc -mno-cygwin' CXX='g++ -mno-cygwin'

Well, if I do that, I get this:

  checking for MAP_ANON in sys/mman.h... no
  checking for /dev/zero... configure: error: cannot check for file
  existence when cross compiling

This comes from the
  AC_CHECK_FILE(/dev/zero)
call in configure.in.

I think this might be an apr m4 macro problem. That's why I was lying 
to configure. Is there standard conventions for getting around this
problem?

Thanks,
Bob Rossi

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