std: align(16) main_thread_tls_buffer
std: align(16) main_thread_tls_buffer

Before this change, thread local variables were landmines if LLVM
decided to optimize any writes to them using vector instructions.

zig-lang/zig,raulgrell/zig,raulgrell/zig,zig-lang/zig,andrewrk/zig,raulgrell/zig,zig-lang/zig,raulgrell/zig,andrewrk/zig,raulgrell/zig