Fixes copying the current state when delivering pending signals by preserving the original magic1 value of the signal's fpstate.
Re-factor AVX detection in test linux.sigcontext and add support to actually test the AVX state on supported machines.
Adds new _runavx and _runavx512 variables to the cmake suite similar to _runcmp, in order to propagate the AVX and AVX512F defines to the template parsers which are usually automatically defined by the compiler.
Updates a comment w.r.t. alignment of a stack variable we're declaring.
Fixes #3756 (closed)