Add cross-platform interrupt signal utility

[dogancanbakir]

Summary

Add a utility function to send interrupt signals to processes in a cross-platform way.

Background

Currently implemented in goflags (projectdiscovery/goflags#241) for the --max-time feature. This functionality could be useful for other tools.

Current Implementation

Unix (interrupt_unix.go):

func sendInterrupt() {
    if p, err := os.FindProcess(os.Getpid()); err == nil {
        _ = p.Signal(os.Interrupt)
    }
}

Windows (interrupt_windows.go):

var (
    kernel32                     = syscall.NewLazyDLL("kernel32.dll")
    procGenerateConsoleCtrlEvent = kernel32.NewProc("GenerateConsoleCtrlEvent")
)

func sendInterrupt() {
    // CTRL_BREAK_EVENT = 1
    procGenerateConsoleCtrlEvent.Call(1, 0)
}

Proposed Location

github.com/projectdiscovery/utils/process or new github.com/projectdiscovery/utils/signal package

Why

• Go's p.Signal(os.Interrupt) is not implemented on Windows
• Windows requires GenerateConsoleCtrlEvent via kernel32.dll
• Multiple tools may need this for graceful shutdown features

References

• NOT SUPPORT send SIGINT to other process on windows? golang/go#28498
• https://pkg.go.dev/github.com/iwdgo/sigint-windows