This is my fork of Portable Coroutine Library (http://www.xmailserver.org/pcl.html) with a few bugfixes.
The problem of original pcl-1.12 code is incorrect estimation of minimal buffer size for stack (CO_MIN_SIZE) in pcl_private.h.
PCL-1.12 believe that CO_MIN_SIZE = 4K is always enough, but it is not so.
For example, on aarch64 the struct sigcontext reserves at least 4K just "for FP/SIMD state and future expansion" (see <asm/sigcontext.h> for aarch64).
So, I need more accurate way to estimate memory buffer sizes for coroutine stacks.
Additionally, I added the co_get_min_stack_size() routine to original API to allow application get known minimal memory requirements for coroutine stack buffers.