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

fusl/src/legacy/ulimit.c

Index: fusl/src/legacy/ulimit.c
diff --git a/fusl/src/legacy/ulimit.c b/fusl/src/legacy/ulimit.c
new file mode 100644
index 0000000000000000000000000000000000000000..1f59e8e619f5588fdd0a1cf3bd394729b3d0192c
--- /dev/null
+++ b/fusl/src/legacy/ulimit.c
@@ -0,0 +1,19 @@
+#include <sys/resource.h>
+#include <ulimit.h>
+#include <stdarg.h>
+
+long ulimit(int cmd, ...)
+{
+	struct rlimit rl;
+	getrlimit(RLIMIT_FSIZE, &rl);
+	if (cmd == UL_SETFSIZE) {
+		long val;
+		va_list ap;
+		va_start(ap, cmd);
+		val = va_arg(ap, long);
+		va_end(ap);
+		rl.rlim_cur = 512ULL * val;
+		if (setrlimit(RLIMIT_FSIZE, &rl)) return -1;
+	}
+	return rl.rlim_cur / 512;
+}