They all have the same toolset name clang-gnu-4.0.1 but they have
different compiler options (C++11, C++14, original C++ standard). My
tests are expected to fail only on Sandia-clang-4.0 but not on the
first 2... I need different toolset names to selectively mark the
failure expected in expected-failure-markup.xml:
<note author="Lorenzo Caminiti">
Most tests use C++11 lambda functions and variadic macros (even
if technically the library itself does not require C++11).
Other toolset using ...~c++11, ...~c++1y prefixes for this, but Sandia does not.