user: implement mlibc as the libc, finally.

It's finally done..

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

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

@@ -0,0 +1,13 @@
+#include <assert.h>
+#include <wchar.h>
+
+int main() {
+	assert(!wcsncasecmp(L"foo", L"foo", 3));
+	assert(!wcsncasecmp(L"foo", L"FOO", 3));
+	assert(!wcsncasecmp(L"fooa", L"FOOB", 3));
+	assert(wcsncasecmp(L"foo", L"bar", 3));
+	assert(!wcsncasecmp(L"fooa", L"FOOA", 4));
+	assert(!wcsncasecmp(L"123abc", L"123AbC", 6));
+
+	return 0;
+}