Merge pull request #89 from yocchi/clang-workaround

Create a __no_return__ macro to flag a function as not returning.
Fixing cpputest.pc file not being installed when using autotools.
cmake: Added TestGMock.cpp and TestGTest.cpp for CppUTestExtTests.
-Adding missing headers on CppUTestExt installation.
Merge pull request #88 from yocchi/cmake-gmock-test

cmake: Added TestGMock.cpp and TestGTest.cpp for CppUTestExtTests.
Merge pull request #91 from katcipis/master

Fix cpputest.pc instalation when using autotools
Disabled clang's Wmissing-variable-declarations.

Wmissing-variable-declarations forces 'extern' declarations before all
global variable definitions.
It is hard to shut up all of warnings because UtestMacros.h has
global variable definitions in its macros.