[Libguestfs] nbdkit / mingw support

[Eric Blake]

On 3/24/20 1:54 PM, Richard W.M. Jones wrote:
> On Tue, Mar 24, 2020 at 01:43:52PM -0500, Eric Blake wrote:
>> On 3/21/20 7:06 AM, Richard W.M. Jones wrote:
>>> Eric:
>>>
>>> Yifan Gu has posted a few patches for mingw support.  My comments
>>> below.
>>>
>>> https://github.com/gyf304/nbdkit/commit/a37c4ca6546dfc4e96e305af97b62e5a9d6174ca
>>>
>>> * I think the SHARED_LDFLAGS idea is good.  I pushed a slightly
>>>    different take on the idea here:
>>>    https://github.com/libguestfs/nbdkit/commit/1d634009ab8e43592065ec469df6312400525cc8
>>>    It's slightly different from what Yifan posted above, because I
>>>    replaced -module -avoid-version -shared with $(SHARED_LDFLAGS),
>>>    adding -no-undefined additionally on mingw.
>>
>> Why are we trying to avoid -no-undefined on other platforms?
> 
> Isn't it because we rely on it, since our plugins need symbols that
> are undefined at link time such as nbdkit_*?

Yes, at the moment they do, but do they need to? We could ship libnbdkit 
which provides just the symbols that plugins can link against, and then 
link our binary nbdkit against that same library, rather than expecting 
our plugins to compile undefined until loaded by our binary.  In other 
words, if the fix is by separating our public functions into a shared 
library for mingw to compile plugins without undefined symbols, why not 
do the same for all platforms?

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
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