user: implement mlibc as the libc, finally.

It's finally done..

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

user/include/mlibc/tests/ansi/wcsdup.c

@@ -0,0 +1,13 @@
+#include <assert.h>
+#include <string.h>
+#include <stdlib.h>
+#include <wchar.h>
+
+int main() {
+	wchar_t *wide_string = L"test string\n";
+	wchar_t *dup_string = wcsdup(wide_string);
+	assert(!memcmp(wide_string, dup_string, (wcslen(wide_string) + 1) * sizeof(wchar_t)));
+	free(dup_string);
+
+	return 0;
+}