libposix: deep refactor; add sys/posixly command

With these changes, libposix (and newlib) can run MirBSD Korn Shell.

qa/lib/newlib/213-sigqueue.c

@@ -0,0 +1,88 @@
+#include <signal.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <time.h>
+#include <errno.h>
+#include <stdlib.h>
+
+void catcher(int sig, siginfo_t *info, void *p) {
+	printf("Signal catcher called for signal %d from %d\n", sig, info->si_pid);
+	exit(1);
+}
+
+void timestamp(char *str) {
+	time_t t;
+
+	time(&t);
+	printf("The time %s is %s", str, ctime(&t));
+}
+
+void echoSIGUSR1(void){
+	int result;
+	struct sigaction sigact;
+	sigset_t waitset;
+	siginfo_t info;
+	union sigval v;
+
+	printf("CHILD pid %d\n", getpid());
+	v.sival_int = 0;
+	sigemptyset(&sigact.sa_mask);
+	sigact.sa_flags = SA_SIGINFO;
+	sigact.sa_sigaction = catcher;
+	sigaction(SIGUSR1, &sigact, NULL);
+
+	sigemptyset(&waitset);
+	sigaddset(&waitset, SIGUSR1);
+
+	sigprocmask(SIG_BLOCK, &waitset, NULL);
+
+	while(v.sival_int < 5){
+		result = sigwaitinfo(&waitset, &info);
+		v.sival_int = 1 + info.si_value.sival_int;
+		printf("CHILD sigqueue %d to %d\n", v.sival_int, info.si_pid);
+		sigqueue(info.si_pid, result, v);
+	}
+}
+
+int main(int argc, char *argv[]) {
+	int result;
+	struct sigaction sigact;
+	sigset_t waitset;
+	siginfo_t info;
+	union sigval v;
+	pid_t child;
+
+	switch(child = fork()){
+	case 0:
+		echoSIGUSR1();
+		exit(0);
+		break;
+	case -1:
+		exit(1);
+		break;
+	default:
+		break;
+	}
+
+	printf("PARENT pid %d sleep(3)\n", getpid());
+	sleep(3);
+	v.sival_int = 0;
+	sigemptyset(&sigact.sa_mask);
+	sigact.sa_flags = SA_SIGINFO;
+	sigact.sa_sigaction = catcher;
+	sigaction(SIGUSR1, &sigact, NULL);
+
+	sigemptyset(&waitset);
+	sigaddset(&waitset, SIGUSR1);
+
+	sigprocmask(SIG_BLOCK, &waitset, NULL);
+
+	result = SIGUSR1;
+	do{
+		printf("PARENT sigqueue %d\n", v.sival_int);
+		sigqueue(child, result, v);
+		result = sigwaitinfo(&waitset, &info);
+		v.sival_int = 1 + info.si_value.sival_int;
+	} while(v.sival_int < 5);
+	exit(0);
+}