user: implement mlibc as the libc, finally.

It's finally done..

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

user/include/mlibc/options/glibc/generic/glibc-assert.cpp

@@ -0,0 +1,14 @@
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <bits/ensure.h>
+
+[[gnu::noreturn]] void __assert_fail_perror(int errno, const char *file, unsigned int line,
+		const char *function) {
+	char *errormsg = strerror(errno);
+	fprintf(stderr, "In function %s, file %s:%d: Errno '%s' failed!\n",
+			function, file, line, errormsg);
+	abort();
+}