[cmake-developers] Remove check for source files in add_library()

[Ben Boeckel]

On Fri, Jun 27, 2014 at 15:48:34 +0200, Ådne Hovda wrote:
> It would be handy when creating macros that wraps add_library where the 
> number of source files is unknown to be able to write:
> 
> add_library( mylib )
> target_sources( mylib PRIVATE mylib.c mylib.h )
> 
> but this fails with the warning "You have called ADD_LIBRARY for library 
> testlib without any source files. This typically indicates a problem 
> with your CMakeLists.txt file"

Why not just defer the add_library until the end of the file?

> I have tried to just remove that check in cmAddLibraryCommand and apart 
> from a warning about missing LINKER_LANGUAGE it works okay.
> 
> https://github.com/aadnehovda/CMake/commit/d527b1db787c426517f7af357df0cd3ba9d9a12a
> 
> I guess there are other implications I have not though of as well?

Does the test suite run without complaint? Also, a test for this would
be appreciated.

--Ben