Add a "fork" of musl as //fusl.

fusl/src/legacy/daemon.c

Index: fusl/src/legacy/daemon.c
diff --git a/fusl/src/legacy/daemon.c b/fusl/src/legacy/daemon.c
new file mode 100644
index 0000000000000000000000000000000000000000..1568b1dcb7517bf0cf1ccb0b094b2dde2f88c59c
--- /dev/null
+++ b/fusl/src/legacy/daemon.c
@@ -0,0 +1,33 @@
+#define _GNU_SOURCE
+#include <fcntl.h>
+#include <unistd.h>
+
+int daemon(int nochdir, int noclose)
+{
+	if (!nochdir && chdir("/"))
+		return -1;
+	if (!noclose) {
+		int fd, failed = 0;
+		if ((fd = open("/dev/null", O_RDWR)) < 0) return -1;
+		if (dup2(fd, 0) < 0 || dup2(fd, 1) < 0 || dup2(fd, 2) < 0)
+			failed++;
+		if (fd > 2) close(fd);
+		if (failed) return -1;
+	}
+
+	switch(fork()) {
+	case 0: break;
+	case -1: return -1;
+	default: _exit(0);
+	}
+
+	if (setsid() < 0) return -1;
+
+	switch(fork()) {
+	case 0: break;
+	case -1: return -1;
+	default: _exit(0);
+	}
+
+	return 0;
+}