user: implement mlibc as the libc, finally.

It's finally done..

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

user/include/mlibc/options/linux/generic/sys-random.cpp

@@ -0,0 +1,21 @@
+
+#include <sys/random.h>
+#include <bits/ensure.h>
+
+#include <mlibc/debug.hpp>
+#include <mlibc/posix-sysdeps.hpp>
+
+#include <errno.h>
+
+ssize_t getrandom(void *buffer, size_t max_size, unsigned int flags) {
+	if(flags & ~(GRND_RANDOM | GRND_NONBLOCK)) {
+		errno = EINVAL;
+		return -1;
+	}
+	MLIBC_CHECK_OR_ENOSYS(mlibc::sys_getentropy, -1);
+	if(int e = mlibc::sys_getentropy(buffer, max_size); e) {
+		errno = e;
+		return -1;
+	}
+	return max_size;
+}