[CMake] CMake build for gnustep/libobjc2 on Ubuntu Touch

[Mathias Bauer]

Hi dear list members,

I have built libobjc2 using CMake with clang on several systems with X86 
or ARM without a problem, but on Ubuntu Touch my build fails and I can't 
figure out what goes wrong.

CMake complains when trying to configure the libobjc2 build:

No C++ runtime library found
Looking for include file pthread.h - not found
Could NOT find Threads (missing: Threads_FOUND)

Of course pthread.h is there (in /usr/include), so something weird 
happened that I would like to track down. Can someone tell me where I 
should start and what is the best way to debug the CMake process?

In case someone is interested:
I took the standard Ubuntu Touch build on a Nexus 10, installed the 
preconditions including build-essentials (gcc is 4.8.2) and built the 
trunk version of clang and installed it. Then I tried to build libobjc2.

Thanks in advance,
Mathias