[CMake] Updated FindThreads.cmake in tracker

[Hendrik Sattler]

Am Sonntag 20 September 2009 17:16:19 schrieb Philip Lowman:
> Hello,
> 
> I've merged (optional) Pthreads-win32 support into a FindThreads.cmake
> attached in the tracker and added some documentation on how to use it.
> Since FindThreads isn't my module I wanted to throw this up on the mailing
> list for feedback.
> 
> http://www.cmake.org/Bug/view.php?id=6399
> 
> 
> Also, in regard to a previous mailing list thread about FindThreads...
> 
> I'm not sure which platform the block "Check if compiler accepts -pthread"
> is executed on.  The documentation I attached to the code advises calling
> "target_link_libraries(target ${CMAKE_THREAD_LIBS_INIT})".  After grokking
> the code a bit further I'm now guessing this "-pthread" argument is
> technically accepted by the linker and not needed by the compiler, but it
> would be nice to know this for sure to ensure the documentation is correct.

gcc says:
-pthread
           Adds support for multithreading with the pthreads library.  This
           option sets flags for both the preprocessor and linker.

So it may work to only use it during linking but this may cause subtle failure 
on some platforms.

When writing FindThreads.cmake, it would be better to really rewrite it and 
use the common naming standards for cmake modules.

HS