user: implement mlibc as the libc, finally.

It's finally done..

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

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

@@ -0,0 +1,22 @@
+#include <assert.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+int main() {
+	errno = 0;
+	void *ptr = calloc((SIZE_MAX / 2) + 2, 2);
+	assert(!ptr);
+	assert(errno);
+
+	errno = 0;
+	ptr = calloc(10, sizeof(size_t));
+	assert(ptr);
+	for(size_t i = 0; i < 10; i++) {
+		size_t *p = ptr;
+		assert(!p[i]);
+	}
+
+	return 0;
+}