clasp requires c++11 threads with 64bit __atomic_exchange, we need to link with libatomic on armel, powerpc, powerpcspe, m68k, mips, mipsel, and sh4, see also https://gcc.gnu.org/wiki/Atomic and https://gcc.gnu.org/wiki/Atomic/GCCMM/LIbrary
Fix 'catch' (CTest) compatibility with glibc-2.34 The clasp package contains an embedded copy of the 'catch' v1 (CTest) library. That copy is outdated and incompatible with glibc-2.34. This patch updates the test sources to use the system provided versions of 'catch' instead, to fix this issue. C.f.: https://github.com/catchorg/Catch2/issues/2178
