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Re: environ: fix link error on 64-bit Cygwin

On 2/26/2018 4:28 PM, Ken Brown wrote:
> On 1/31/2018 9:40 AM, Corinna Vinschen wrote:
>> On Jan 31 07:52, Eric Blake wrote:
>>> Forwarding from the gnulib list; is this something we should fix in
>>> cygwin proper?
>> Why does anybody remove the -Wl,--disable-auto-import flag?  What for?
>> The idea was to never use this flag on Cygwin and to get rid of the
>> dllimport/dllexport nonsense...
>>> On 01/31/2018 04:42 AM, Bruno Haible wrote:
>>>> On 64-bit Cygwin, a libunistring build fails like this:
>>>> [...]
>>>> libtool: link: x86_64-pc-cygwin-gcc -g -O2 -Wl,--disable-auto-import
>>>> -o .libs/test-environ.exe test-environ.o  -L/usr/local/cygwin64/lib
>>>> libtests.a ../lib/.libs/libunistring.dll.a -liconv libtests.a
>>>> -L/usr/local/cygwin64/lib
>>>> test-environ.o:test-environ.c:(.rdata$.refptr.environ[.refptr.environ]+0x0):
>>>> undefined reference to `environ'
>>>> collect2: error: ld returned 1 exit status
>>>> This fixes it.
>>>> [...]
>>>> +_GL_EXTERN_C __declspec(dllimport) char **environ;
>> But, other than that, an equivalent newlib patch would be ok.
> Before patching newlib, please note that Bruno's patch doesn't work on
> 32-bit Cygwin.  Projects (like emacs and clisp) that use gnulib's unistd
> module with that patch will get link errors like this:
>   undefined reference to `_imp__environ'
> I have no idea why this error occurs only on 32-bit.
> I've made Bruno aware of the problem, and I'm waiting to see what he
> comes up with.

_imp__environ?  Shouldn't that be _imp_environ for Cygwin?
_imp__environ to me indicates the VC version of char **_environ instead.
 Is the correct header being used?

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