[cmake-developers] Ninja: Regressions re. def file handling with MSVC

[Amine Khaldi]

Hi,

Please note that commit a2514f15fae34abb6f29dddf6f5cfe8b171a8035 broke 
the handling of def files when using MSVC. We get errors like:

ninja: ERROR: 'reactos\base\applications\kbswitch\kbsdll\kbsdll.def', 
needed by 'base\applications\kbswitch\kbsdll\kbsdll.dll', missing and no 
known rule to make it

I found this revision by doing a bisect, I hope this will help solving 
this issue.

In the gcc build we declare this generated def as an external object, 
but if I do the same with the MSVC build, the def file gets inserted 
into the link command twice:
* The first one directly, i.e. link.exe /nologo <the def file here> <the 
rest of the link command>
* The second time, it's passed using a /DEF:<the def file>

Needless to say, the first insertion is spurious and invalid, and it 
triggers " <def file> : fatal error LNK1107: invalid or corrupt file: 
cannot read at 0x3BBD.

Regards,
Amine.