user: implement mlibc as the libc, finally.

It's finally done..

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

user/include/mlibc/tests/posix/posix_memalign.c

@@ -0,0 +1,23 @@
+#include <stdlib.h>
+#include <assert.h>
+#include <stdint.h>
+#include <errno.h>
+
+int main() {
+	void *p = NULL;
+
+	// align must be a power of two
+	assert(posix_memalign(&p, 3, 1) == EINVAL && p == NULL);
+
+	// align must be a multiple of sizeof(void *)
+	assert(posix_memalign(&p, sizeof(void *) / 2, 8) == EINVAL && p == NULL);
+
+	assert(posix_memalign(&p, sizeof(void *), sizeof(void *)) == 0 && p != NULL && (uintptr_t)p % sizeof(void *) == 0);
+	free(p);
+	assert(posix_memalign(&p, 256, 1) == 0 && p != NULL && (uintptr_t)p % 256 == 0);
+	free(p);
+	assert(posix_memalign(&p, 256, 256) == 0 && p != NULL && (uintptr_t)p % 256 == 0);
+	free(p);
+
+	return 0;
+}