Jonny - I just tested lp:qwwad r135.  Build log through out a linker error (can't find pthread).  Any immediate solution?  I ran it as an out-of-source build.  Here's a transcript

$ mkdir build-cmake
$ cd build-cmake/
$ CC=clang CXX=clang++ cmake ../
-- The C compiler identification is Clang 3.4.0
-- The CXX compiler identification is Clang 3.4.0
-- Check for working C compiler: /usr/bin/clang
-- Check for working C compiler: /usr/bin/clang -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/clang++
-- Check for working CXX compiler: /usr/bin/clang++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Looking for dgemm_
-- Looking for dgemm_ - found
-- Looking for include file pthread.h
-- Looking for include file pthread.h - found
-- Looking for pthread_create
-- Looking for pthread_create - not found
-- Looking for pthread_create in pthreads
-- Looking for pthread_create in pthreads - not found
-- Looking for pthread_create in pthread
-- Looking for pthread_create in pthread - found
-- Found Threads: TRUE  
-- A library with BLAS API found.
-- Looking for cheev_
-- Looking for cheev_ - found
-- A library with LAPACK API found.
-- Boost version: 1.54.0
-- Configuring done
-- Generating done
-- Build files have been written to: /home/alex/devel/qwwad/lp-qwwad-ch/build-cmake

$ make 
Scanning dependencies of target gtest
[ 33%] Building CXX object gtest/CMakeFiles/gtest.dir/src/gtest_main.cc.o
[ 66%] Building CXX object gtest/CMakeFiles/gtest.dir/src/gtest-all.cc.o
Linking CXX static library libgtest.a
[ 66%] Built target gtest
Scanning dependencies of target tests
[100%] Building CXX object tests/CMakeFiles/tests.dir/some_tests.cpp.o
Linking CXX executable tests
../gtest/libgtest.a(gtest-all.cc.o): In function `testing::internal::ThreadLocal<std::vector<testing::internal::TraceInfo, std::allocator<testing::internal::TraceInfo> > >::~ThreadLocal()':
/home/alex/devel/qwwad/lp-qwwad-ch/gtest/src/gtest-all.cc:(.text._ZN7testing8internal11ThreadLocalISt6vectorINS0_9TraceInfoESaIS3_EEED2Ev[_ZN7testing8internal11ThreadLocalISt6vectorINS0_9TraceInfoESaIS3_EEED2Ev]+0x16): undefined reference to `pthread_getspecific'
/home/alex/devel/qwwad/lp-qwwad-ch/gtest/src/gtest-all.cc:(.text._ZN7testing8internal11ThreadLocalISt6vectorINS0_9TraceInfoESaIS3_EEED2Ev[_ZN7testing8internal11ThreadLocalISt6vectorINS0_9TraceInfoESaIS3_EEED2Ev]+0x2e): undefined reference to `pthread_key_delete'
../gtest/libgtest.a(gtest-all.cc.o): In function `testing::internal::ThreadLocal<testing::TestPartResultReporterInterface*>::~ThreadLocal()':
/home/alex/devel/qwwad/lp-qwwad-ch/gtest/src/gtest-all.cc:(.text._ZN7testing8internal11ThreadLocalIPNS_31TestPartResultReporterInterfaceEED2Ev[_ZN7testing8internal11ThreadLocalIPNS_31TestPartResultReporterInterfaceEED2Ev]+0x19): undefined reference to `pthread_getspecific'
/home/alex/devel/qwwad/lp-qwwad-ch/gtest/src/gtest-all.cc:(.text._ZN7testing8internal11ThreadLocalIPNS_31TestPartResultReporterInterfaceEED2Ev[_ZN7testing8internal11ThreadLocalIPNS_31TestPartResultReporterInterfaceEED2Ev]+0x2c): undefined reference to `pthread_key_delete'
../gtest/libgtest.a(gtest-all.cc.o): In function `testing::internal::ThreadLocal<std::vector<testing::internal::TraceInfo, std::allocator<testing::internal::TraceInfo> > >::CreateKey()':
/home/alex/devel/qwwad/lp-qwwad-ch/gtest/src/gtest-all.cc:(.text._ZN7testing8internal11ThreadLocalISt6vectorINS0_9TraceInfoESaIS3_EEE9CreateKeyEv[_ZN7testing8internal11ThreadLocalISt6vectorINS0_9TraceInfoESaIS3_EEE9CreateKeyEv]+0x15): undefined reference to `pthread_key_create'
../gtest/libgtest.a(gtest-all.cc.o): In function `testing::internal::ThreadLocal<testing::TestPartResultReporterInterface*>::CreateKey()':
/home/alex/devel/qwwad/lp-qwwad-ch/gtest/src/gtest-all.cc:(.text._ZN7testing8internal11ThreadLocalIPNS_31TestPartResultReporterInterfaceEE9CreateKeyEv[_ZN7testing8internal11ThreadLocalIPNS_31TestPartResultReporterInterfaceEE9CreateKeyEv]+0x15): undefined reference to `pthread_key_create'
../gtest/libgtest.a(gtest-all.cc.o): In function `testing::internal::ThreadLocal<testing::TestPartResultReporterInterface*>::GetOrCreateValue() const':
/home/alex/devel/qwwad/lp-qwwad-ch/gtest/src/gtest-all.cc:(.text._ZNK7testing8internal11ThreadLocalIPNS_31TestPartResultReporterInterfaceEE16GetOrCreateValueEv[_ZNK7testing8internal11ThreadLocalIPNS_31TestPartResultReporterInterfaceEE16GetOrCreateValueEv]+0x1c): undefined reference to `pthread_getspecific'
/home/alex/devel/qwwad/lp-qwwad-ch/gtest/src/gtest-all.cc:(.text._ZNK7testing8internal11ThreadLocalIPNS_31TestPartResultReporterInterfaceEE16GetOrCreateValueEv[_ZNK7testing8internal11ThreadLocalIPNS_31TestPartResultReporterInterfaceEE16GetOrCreateValueEv]+0x9c): undefined reference to `pthread_setspecific'
../gtest/libgtest.a(gtest-all.cc.o): In function `testing::internal::ThreadLocal<std::vector<testing::internal::TraceInfo, std::allocator<testing::internal::TraceInfo> > >::GetOrCreateValue() const':
/home/alex/devel/qwwad/lp-qwwad-ch/gtest/src/gtest-all.cc:(.text._ZNK7testing8internal11ThreadLocalISt6vectorINS0_9TraceInfoESaIS3_EEE16GetOrCreateValueEv[_ZNK7testing8internal11ThreadLocalISt6vectorINS0_9TraceInfoESaIS3_EEE16GetOrCreateValueEv]+0x1c): undefined reference to `pthread_getspecific'
/home/alex/devel/qwwad/lp-qwwad-ch/gtest/src/gtest-all.cc:(.text._ZNK7testing8internal11ThreadLocalISt6vectorINS0_9TraceInfoESaIS3_EEE16GetOrCreateValueEv[_ZNK7testing8internal11ThreadLocalISt6vectorINS0_9TraceInfoESaIS3_EEE16GetOrCreateValueEv]+0x9c): undefined reference to `pthread_setspecific'
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [tests/tests] Error 1
make[1]: *** [tests/CMakeFiles/tests.dir/all] Error 2
make: *** [all] Error 2