.github/workflows: update async.yml, multi-arch.yml, multi-compiler.yml, no-malloc.yml, opensslcoexist.yml, and os-check.yml, with -pedantic and related flags, and add --enable-riscv-asm to multi-arch.yml RISC-V scenario;
configure.ac: clarify error message for "SP ASM not available for CPU."
* First attempt with GCC only
* Make the test run on every push temporarily
Also clean up the description of the workflow
* Fix invalid job name
* Missing hunks added
* Try out matrix actions
* Fix missing 'runs-on'
* Only needs to run on Ubuntu
* Use local installations of gcc/clang instead of containers
* Explicitly list out compilers to test
* Clean up names and concurrency group
* Only need to run on PRs and important branches
Co-authored-by: Andras Fekete <andras@wolfssl.com>
