Add dynamic memory allocation function definitions

Add malloc, calloc, realloc, free and memalign declarations to stdlib.h
and malloc.h.

Signed-off-by: Imre Kis <imre.kis@arm.com>
Change-Id: I1f268fcb77e4234a712e2ac59d59d453abea2690
diff --git a/components/common/libc/include/malloc.h b/components/common/libc/include/malloc.h
new file mode 100644
index 0000000..275211d
--- /dev/null
+++ b/components/common/libc/include/malloc.h
@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2024, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef MEMORY_H
+#define MEMORY_H
+
+#include <stddef.h>
+
+/*
+ * The declaration of this function is part of libc but it is implemented in
+ * the allocator.
+ */
+void *memalign(size_t alignment, size_t size);
+
+#endif /* MEMORY_H */
\ No newline at end of file