A nim-ffi library is loaded into a foreign host (Go/Rust/...) that must
own OS signal handling; if the Nim runtime installs its own handlers it
clobbers the host's (e.g. Go's SIGSEGV -> sigpanic recovery, stack
growth, goroutine preemption), turning recoverable faults into hard
process crashes. The flag can only be set on the consumer's final build
command, so a dependency cannot inject it -- but it CAN refuse to
compile without it. Add a compile-time guard so any consumer that omits
-d:noSignalHandler fails the build with an actionable message instead of
crashing at runtime (the cause of a real status-go regression).
Standalone Nim binaries (nim-ffi's own tests) build with
-d:ffiAllowSignalHandler.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
* protect against mem leak in case of failures sending requests to ffi thread
* better cleanup if failures in createFFIContext
* avoid dangling cstring in handleRes under ARC/ORC
* better resource cleanup in destroyFFIContext
* invoke onNotResponding if failure in destroyFFIContext
* correct seq copy in alloc
* make sure the lock is init before cleanUpResources
* better possible exception handling in processReq
* guard allocSharedSeq if given seq is empty
* enhance error handling in ffi_context
* add new tests and some corrections
