user: implement mlibc as the libc, finally.

It's finally done..

Signed-off-by: kaguya <vpshinomiya@protonmail.com>

user/include/mlibc/sysdeps/vinix/generic/mount.cpp

@@ -0,0 +1,16 @@
+#include <errno.h>
+#include <sys/mount.h>
+#include <bits/ensure.h>
+
+int mount(const char *source, const char *target,
+		const char *fstype, unsigned long flags, const void *data) {
+	return 0;
+}
+
+int umount(const char *target) {
+	return umount2(target, 0);
+}
+
+int umount2(const char *target, int flags) {
+	return 0;
+}